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Collect screen paperboard of mine power transformer and ordinary power transformer in practical lifetime cycle to make insulation test samples, and according to the standard of power, use test means such as viscosity tester, scanning electron microscopy to compare and analyze microstructures of insulation paper such as polymerization degree, surface morphology of mine power transformer and ordinary power transformer, as well as electrical properties such as partial discharge and electrical strength; at the same time, effect of microstructure changes on electrical performances during aging was discussed. The analysis results show that the insulation defects gradually form and expand in the insulation paper during the aging process; compared with the insulation paper of ordinary power transformers, the surface morphology changes of the insulation paper of mine power transformers are more obvious, and the formed defects are more significant.In the aging process, the polymerization degree of insulation paper of ordinary power transformer and mine power transformer presents a gradual decline trend, but the decline speed of polymerization degree of mine power transformer insulation paper is faster.The operating environment of mining area is the main reason that the aging of insulation paper of mine power transformer is more serious than that of ordinary power transformer.In the process of operation, the insulation paper of mine power transformer will produce more discharge quantity, more discharge times and wider discharge phase than ordinary power transformer.In the aging process, the electrical strength of insulation paper of both ordinary power transformer and mine power transformer decreases gradually, but the electrical strength of insulation paper of mine power transformer is lower than that of ordinary power transformer.The microstructural defects of insulation paper of mine power transformers are the direct causes of the more significant changes in their electrical properties.In the process of state monitoring and maintenance of power equipment, it is suggested that the insulation state monitoring of mine power transformers should be carried out strictly according to the power standards,electrical property parameters are more suitable for insulation status monitoring and fault diagnosis of mine power transformer.

Application principle of polarization spectrum method based on recovery voltage method was introduced which was used in state detection of transformer oil-paper insulation, and a viewpoint was pointed out that main time constant of polarization spectrum curve was an important factor for judging state of transformer oil-paper insulation. Influence of charging voltage, residual charge and temperature on measurement result of polarization spectrum curve was analyzed separately with conclusions that charging voltage only influenced the maximal value of recovery voltage but did not influence main time constant of polarization spectrum curve, and residual charge and temperature would influence the main time constant. Matters needed attention were proposed that transformer should be fully discharged firstly, charging voltage should be as high as possible in range of 0-2 000 V and environmental temperature should be stable during actual application of polarization spectrum method based on recovery voltage method in state detection of transformer oil-paper insulation.

An online intelligent examination system of coal mining enterprises was proposed based on analysis of actual examination requirements of enterprise employees. A Web examination system is built firstly according to professional characteristics of the employees, and the system is optimized functionality. Secondly, GAAA algorithm integrated with genetic algorithm and ant algorithm is improved. The improved GAAA algorithm firstly updates ant colony pheromone, then searches test database by a comprehensive search of genetic algorithm and parallel distribution of ant algorithm for optimizing group volume of the database. At last, the improved GAAA algorithm is applied in the system to achieve examination of employees at anytime they like and anywhere they are and auto-generating examination paper. The practical application shows that speed of auto-generating examination paper of the system is high, repetition rate is low, the algorithm is feasible, and the system can meet practical requirements of online examination effectively and improve online examination efficiency of coal mine enterprise.

The paper introduced structure and key technologies of mine-used intrinsically safe wireless through-the-earth communication system，and analyzed working principle of the system. The system uses low-frequency electromagnetic radiation technology, digital communication technology and intrinsically safe power supply technology, which has characteristics of smaller volume, lighter weight and easy operation. The test results of prototype show that the system has realized two-way through-the-earth communication for 50 m with communication rate of about 150 bit/s and bit error rate of no larger than 0.2 %, and has a certain practical value

In view of problem that 35 kV power system of a Coal Mine often happens over-voltage at thunderstorm day, the paper analyzed causes of over-voltage, indicated that over-voltage was induced by fraction frequency resonance and the fraction frequency resonance was induced by PT and capacitance to earth of overhead line. Through analyzing parameters of resonance over-voltage of the power system, it gave corresponding reform scheme, namely replacing PT with better excitation voltammetry characteristic, adding nonlinear harmonic eliminator at neural point of high-voltage side of PT and installing intelligent resonance eliminating device with multifunction. The actual application showed that 35 kV power system has not happened resonance over-voltage with reliable running after using the reform scheme.

In view of problem of difficult location of fault existed in real time fault detection methods of powerful conveyor belt, the paper proposed an identification algorithm of joints of powerful conveyor belt based on image processing technology which takes a joint as a reference point. Firstly, based on the characteristics of joint points, a joint point is represented by a value. According to the value, upper or lower joint point could be distinguished simply. Then according to the features of joints, matching style of the longest common subsequence algorithm was modified and applied to recognize joint. The practical application showed that the algorithm has high precision and fast speed, can efficiently recognize joints of powerful conveyor belt and satisfy demand of joint locating of fault detection of powerful conveyor belt.

For problems that underground broadcasting system with analog audio broadcasting mode has poor flexibility and small voice communication range, the paper proposed design scheme of a new kind of mine-used digital broadcasting system, introduced designs of overall structure of the system, audio terminal and gateway program. The system accesses the audio terminal in industrial Ethernet, realizes packet and designated broadcasting, which solves problems of underground unicast and multicast.

With the continuous increase of coal mining depth, the occurrence and prevention of deep rockburst in China have become normalized. In order to improve the effectiveness of deep rockburst prevention and control technology, starting from the technical difficulties of deep rockburst prevention and control in on-site engineering, combined with practical data statistics of disaster prevention and control engineering, this study demonstrates that the deep rockburst in China is due to its high geological stress and large range of human mining disturbance. The stress recovery of surrounding rock is fast after rock stress unloading during the disaster prevention and control process. The low effectiveness of rockburst prevention and control can be attributed to the new requirements of “three highs and one low” prevention and control technology in deep mining compared to that in shallow mining, including high-strength large-sized drilling to relieve pressure, in order to solve the collapse prone problem of thick and hard coal seams; small spacing high-density drilling to solve the problem of disconnected pressure relief range in drilling; multiple rounds of repeated high-frequency construction to solve the problem of rapid stress recovery after unloading pressure in deep coal seams; and the mining face is advancing at a low speed to solve the problem of high mining disturbance intensity. In response to the new requirements of “three highs and one low” prevention and control mode for deep rockburst, in order to further improve the safety and reliability of rockburst prevention and control, and based on the limitations of optimizing development and mining deployment for conventional source rockburst prevention and control, this paper proposes the technology of actively regulating the structure and load of overlying rock layers in the deep rockburst prevention and control areas, and presents some further scientific problems that need to be solved. Against the background of several typical rockburst accidents in recent years with the problem of “missed targets” in the prevention and control plans, a local targeted prevention and control technology for deep rockburst mining space has been developed, and the scientific challenges that need to be solved in the future have been pointed out. Against the background of the difficulty in evaluating safety issues after the implementation of coal mine rockburst prevention and control measures, a deep rockburst prevention and control unloading standard evaluation technology is proposed, and the scientific difficulties that need to be solved in the future are pointed out. The coal industry vigorously promotes intelligent mining, but the disaster control still relies on manual labor and personnel to operate in a high-risk environment. This paper also explores the emerging research direction and scientific challenges of intelligent mining and intelligent prevention and control of deep rockburst. Finally, it is objectively pointed out that the prevention and control of rockburst is not purely a theoretical and technical issue, and the human understanding of technical issues is also one of the important reasons for rockburst accidents. Combining with the on-site engineering practice, this paper discusses the concept and mechanism of rockburst, whether rockburst can be predicted, whether rockburst can be prevented and controlled, and how to deal with rockburst mines and other industry focused technical issues. It is pointed out that the problem of rockburst engineering is a struggle between humans and nature, which requires practitioners to objectively understand, objectively accept, and conduct in-depth research. The current achievement is of significance.

In order to improve the production of coalbed methane vertical wells in the central and northern Zhengzhuang block, southern Qinshui Basin, Shanxi, China, this paper analyzes the reasons for the poor stimulation effect of medium-deep coalbed methane vertical wells, based on the ground stress test data and fracturing monitoring data of these evaluation wells in the study area, proposes targeted stimulation techniques, designs and carries out field comparative pilot studies and analyzes their results. The results show that there are three main reasons for the low production of these vertical wells in the study area. Firstly, the vertical fracture is dominant, resulting in the shorter length of hydraulic fractures. With the increase of burial depth, the length and width of fractures decreases at the same fracturing scale. Secondly, with the increase of burial depth, the embedment depth of proppants into coal rock increases and the closure of hydraulic fractures speeds up. As a result, the stable production time is short, and the main form of gas production curve is “single peak” type. Thirdly, after the initial fracturing, the coal body structure is much more broken, and new fractures are easy to enter the initial fractures, which increases the difficulty of creating new fractures, resulting in poor stimulation effect. In view of the above reasons, the paper proposes an innovative technology of pre-plug, large-scale and remote-support re-fracturing. Pre-plug means that relatively low displacement, sand ratio and scale are first used to fill initial fractures, and then large-scale re-fracturing is carried out to create new fractures. Large-scale fracturing refers to the fracturing with large displacement, large fluid volume and high sand ratio. In order to improve the stimulation effect of middle-deep reservoirs, the fracturing fluid volume is increased from 600−800 m3 to more than 1 300−2 000 m3, the displacement is increased from 6−8 m3/min to more than 10−14 m3/min, and a low viscosity fracturing fluid system combined with low density proppants is used to increase the sand ratio from 7%−8% to more than 10%−15%. Remote-support is a combination of self-suspended proppants and large displacement to increase proppants migration distance and increase the proportion of the propped fractures. The average daily production of a single well reached 1 380 m3, which was 1 190 m3 higher than that before, and nearly 1 000 m3 higher than the stable gas production of adjacent wells, realizing the production breakthrough of vertical wells in the low-production area of the middle-deep reservoir in the north of Zhengzhuang block. Results of the comparative pilot studies showed that the average net construction pressure increased by 3.3 MPa after pre-plug, compared with the initial fracturing, which means that new fractures were formed and resulted in the production increase by 1 000 m3 compared with that of the wells without the Pre-plug. The pilot results show that, in general, the larger the technical parameters of pre-plug, large-scale and remote-support re-fracturing, the better the production performance.

Aiming at the problems of low efficiency of coal mine data utilization and less data sharing caused by the lack of standardized coal mine data model, this paper studies the three-dimensional spatial multivariate data relationship and attribute data planning of coal mines. The process and algorithm from mining engineering plan to tunnel 3D modeling are given, the coal mine data model based on ORM mapping is formed, and the 3D model is output under WebGL technology system. The results shows that the spatial data model established in this paper has high storage and utilization efficiency, and can provide support for data utilization and analysis of mine safety information intelligent decision-making.

In order to utilize high-rank coal efficiently and cleanly, based on Shanxi lean coal, this paper explores the molecular structure characteristics of lean coal and constructs a molecular model of lean coal. In this paper, X-ray photoelectron spectroscopy (XPS) and solid-state nuclear magnetic resonance carbon spectroscopy （13C NMR） were used to characterize and analyze the element occurrence and carbon atom structure of lean coal, and a macromolecular model of lean coal was constructed and optimized. The results showed that the molecular aromatic structure of lean coal was composed of 1 naphthalene, 8 anthracene, 1 tetraphenylene, 1 pyrene, 2 pyridine, 2 pyrrole and 1 thiophene. The oxygen-containing structure includes two intramolecular oxygen-bonded aliphatic carbons, two oxygen-substituted aromatic carbons and one carbonyl carbon. Aliphatic hydrocarbons are composed of 2 fatty methyl groups, 3 aromatic methyl groups, 2 methylene groups and 4 methylene groups. The final macromolecular model of lean coal is C200H140O5N4S. After the initial model was optimized, the valence energy and non-bond energy of coal molecules decreased, but the valence electron energy of coal molecules in the final model was higher than that of non-bond energy, which was the main part of the total energy. Therefore, from the point of view of the adsorption space that the surface of lean coal can provide for gas, the adsorption advantage of CO2 gas in lean coal is stronger than CH4 gas.

Aiming at the problem of high leakage rate and false alarm rate of traditional statistical methods for abnormal fluctuation in sensor monitoring data caused by dampers opening and closing, a SSA-LSTM wind speed abnormal fluctuation detection method based on the combination of Singular Spectrum Analysis (SSA) and Long and Short-Term Memory Neural Network (LSTM) was proposed by mining the data features in the time-series data in the wind speed sensors. Firstly, SSA was used to pre-process the wind speed sensor monitoring data, and the wind speed data was decomposed into trend component, periodic component and noise component. The data noise generated by turbulent pulsation was removed via reorganizing the trend component and noise component. The LSTM parameters was then optimized, and the optimized LSTM model was used to predict the pre-processed data and obtain the reconstructed wind speed. Finally, the anomaly fraction of the monitored wind speed and reconstructed wind speed was calculated by using the logarithmic probability density function. Anomaly detection for monitoring wind speed was performed by calculating the threshold set value of training set data samples. The experimental results shown that, the removing effect for the data noise generated by turbulence pulsation via SSA was better. Removing the noise component without affecting the data fluctuation was helpful in improving the wind speed reconstruction effect and the anomaly detection accuracy. LSTM can correctly reconstruct the small amplitude wave due to turbulence pulsation without anomalous fluctuation and fits well with the actual data. The reconstruction of abnormal fluctuation segment based on historical fluctuation trend when there was abnormal fluctuation can effectively improve the accuracy of anomaly detection. Through comparative analysis, the reconstruction effect of proposed method in this paper was better than ARIMA, BP and CNN models, with an anomaly detection accuracy of 99.2% and an F1-Score of 0.97, which verified the reliability of the proposed method. The method proposed in the paper has important application value in detecting the abnormal fluctuation of wind speed caused by the opening and closing of dampers.

Studying the interaction between coal slime and flotation agents will be the hot and difficult point of flotation process strengthening. In view of the strong hydrophilic chemical structure characteristics of the surface of difficult flotation coal, this paper introduces the bio-pharmaceutical induced fit effect into the study of the interaction of polar collectors in difficult flotation coal flotation. In this paper, 3D coal molecular structure was optimized and constructed according to the results of coal sample properties. Protomol technology was used to search and represent the active pockets of coal molecules, and the optimal conformation of molecular butt between polar collector and difficult floating coal was searched in the active pockets. According to the binding energy of the optimal conformation of the interaction between polar chemicals and coal molecules, the correspondence between the molecular docking results, induced fit effect and the flotation results was analyzed. The molecular docking results and the recovery rates of refractory coal combustible are both lauryl alcohol< lauraldehyde< methyl laurate, The recovery rate of flotation fuels is positively correlated with the absolute value of molecular docking binding energy and the molecular induced binding effect of coal, which revealed the guiding effect of molecular docking on flotation reagent screening. According to the molecular docking configuration, the differences in binding energy can be attributed to the differences of π-CH interaction and steric hindrance. Furthermore, the three-dimensional space of pharmaceutical molecules was fixed and the induced fit effect between three polar collectors and coal molecules was explored by molecular mechanics simulation. It was found that methyl laurate and the active region of coal molecules could generate greater interaction, and the active region of coal molecules had stronger induction effect and inclusion of methyl laurate, so it had better effect in the flotation process. The application of molecular docking and induced fit effect technology in the field of biomedicine to the field of flotation reagents can provide technical approaches and scientific guidance for the rapid screening of flotation collectors.

Coal has made important contributions to the industrialization process of human society, and has played a key supporting role in ensuring China’s energy security and stable economic development. Since the mid-19th century, the coal-based fuel of coal, kerosene, gas and coal electricity has gradually entered the era of large-scale use. However, the traditional use of coal produces high carbon emissions, which has become a major problem in energy transition. Facing the development of ecological civilization society, the clean and efficient use of coal is imminent, and the innovation of modern coal-based energy technology is imperative. This paper proposes the definition and connotation of modern coal-based energy technology system, which is defined as the production of low-carbon energy products such as coal-based gas, coal-based oil, coal-based hydrogen and coal-based electricity, and the in-situ absorption of carbon dioxide in mining areas to form a clean and low-carbon energy production system with carbon neutrality. Its technical connotation includes coal-based gas, coal-based oil, coal-based hydrogen, coal-based electricity and dynamic carbon neutrality in mining areas, with a total of 5 technical modules, 19 technical units and 61 key technologies. The modern coal-based energy technology system will play an important role of “one main body, three supports and one breakthrough” in the future new energy system. Coal-based electricity provides the main body of electricity system stability. Coal-based oil supports the China’s oil safety. Coal-based gas supports the China’s gas safety. Coal-based hydrogen plays a supporting role in the development of hydrogen energy in China. The major breakthrough is the dynamic carbon neutral technology of coal-based energy. The paper supposes that when the ratio of non-fossil energy and low-carbon coal-based energy is maintained in the range of 2.5−3.0, coal-based energy, oil and gas and wind, water, nuclear energy can be reasonably integrated to form a new quality energy system with strong complementarity, high reliability and low carbon emissions. Based on the major breakthrough and practical application of modern coal-based energy technology, it is predicted that China’s low-carbon coal-based energy production will reach 1.02 billion −1.46 billion tons of standard coal equivalent (tce) in 2060, equivalent to 18%−24% of the national energy demand, and carbon dioxide emissions will be controlled below 500 million tons. Compared with the current energy transformation planning path based on “de coal” planning, the share of coal in our energy system can increase from 10% to more than 20%, and carbon dioxide emissions will reduce by 50%. At that time, the modern coal-based energy system has great technological innovation significance for China’s energy security and carbon dioxide emission reduction, and helps China to become a country with independent energy supply.

During the coal mining process, the change in the floor stress state of coal seam will produce deformation and failure. The seam floor failure in different coal mining processes has a certain law. At present, the water disaster monitoring of coal seam floors based on the DC resistivity method mainly focuses on the resistivity response characteristics of floor deformation and damage. To investigate the temporal changes in the electrical properties of the coal seam floor during mining, this study employs the inter-hole DC perspective observation system and the time-lapse resistivity reflection coefficient method. Through numerical simulation and field tests, the study uncovers the temporal variation law of the resistivity of coal seam floor induced by mining activities. First, this paper compares the results of individual inversion and time-lapse resistivity change rates for a typical geoelectric model to validate the reliability of the inter-hole DC perspective time-lapse method. Next, considering the mining-induced damage to the coal seam floor, this paper analyzes the electrical response patterns and charac-teristics of the rise of confined water and the damage zone in the floor during the mining process. It also discusses the feasibility of using a time-lapse resistivity reflection coefficient to assess the depth of coal seam floor damage, offering a theoretical basis for field construction. Finally, , the on-site monitoring tests reveal the electrical change characteristics of coal seam floor during the coal mining process. The time-lapse resistivity reflection coefficient R is utilized to determine the damage depth of the rock layer of the working face floor, which is found to be 15 m. The study results demonstrate that the time-lapse characteristics of the resistivity of coal seam floor mining damage obtained by the inter-hole DC perspective method can mitigate the influence of formation factors and random noise in the monitoring data to a certain extent. Additionally, the time-lapse resistivity reflection coefficient can be utilized to determine the depth of coal seam floor failure. This method transforms the detection target from the single study of geological anomalies to the full life cycle dynamic monitoring of the floor damage of the working face in the process of coal mining and then realizes the detailed depiction of structural damage to the working surface floor.

Based on the green development trend and requirements of China’s coal industry, this paper analyzed the factors that coal mines consider in choosing filling mining methods and the constraints that affect the promotion of filling mining technology. According to the geographical distribution characteristics of different mining areas and the differences in filling demands, four types of priority principles of “protecting the ecological environment, protecting surface buildings, addressing coal gangue and solid waste, and improving economic efficiency” for coal mine filling mining were defined. The ecological mining goal of “building the whole process holographic intelligent ecological mine by adopting filling mining as a regulation tool to protect the ecological environment in coal mines” was put forward. Based on the finite deformation mechanical model of the roof in filling mining, the factors affecting the subsidence of target rocks in filling mining were expounded, and the supporting strength calculation and overburden deformation control equations under three filling engineering modes such as ecological environment protection, ground building protection and gangue treatment were established. In addition, the paper introduced the development status and direction of universal filling technology in coal mines in China, including solid filling of raw gangue waste, modified solid filling, gangue concrete filling, integrated mining-filling-charging, large amount of gangue filling, filling method in thin coal seam, filling method for regional protection, filling method in continuous mining roadway and other filling technologies that meet various needs of coal mines. The material preparation and transportation of different filling technologies, the characteristics of filling process and the adaptive filling equipment were described in detail. In order to realize the intelligent filling of coal mines, a comprehensive data perception system was established, which realized the intelligent process from unit to whole filling working face through spatial planning and filling effect judgment. The sensor network and artificial intelligence algorithm were combined to monitor and control the solid filling process of coal mine in real time, and improve the filling quality and filling efficiency. Coal mine filling mining will play a more important role in the long-term planning of China’s green mine construction. Strengthening the scientific and technological research of the whole process of coal mine production based on active filling, the construction of universal filling technology and process system, the development of new solid filling materials, and the research of intelligent filling mining, will help the filling mining technologies in China’s coal mines have a very broad prospect.

The MILD combustion is a combustion mode that occurs in a moderate or extremely low oxygen environment, combining the advantages of high combustion heat utilization and very low NOx emissions, and is considered by the international combustion field to be one of the cleaner combustion technologies with great potential for application. Since the relevant research began around 1990, the technology for achieving a MILD combustion of gas fuels has been relatively mature, while the research on the MILD combustion mechanism and implementation conditions of solid fuels such as coal powder and biomass is still relatively lacking. Based on the high momentum oxidizer jet, internal recirculation is achieved, eliminating the need for external high-temperature preheating to establish MILD combustion, greatly expanding the application range of MILD combustion. This paper provides an overview of the basic characteristics of MILD powder fuel combustion from the aspects of particle dispersion, heating, ignition, combustion, and pollutants. Due to the uneven dispersion and reaction of particles, the MILD combustion process of carbon-based solid fuels such as coal powder is more complex than that of gas fuels. High speed jet MILD combustion not only increases ignition delay but also expands ignition and reaction zones, requiring systematic research on the characteristics and mechanisms of each combustion stage. This paper introduces the research achievements in the theoretical design and equipment development of solid fuel MILD combustion. It is recommended to improve the existing coal-fired boiler burner, adjust the process parameters to match the MILD combustion mode, increase the residence time of coke particles to improve combustion efficiency, improve combustion stability, and suppress various pollutant emissions, including fine particulate matter, through high-precision numerical simulation. Based on the overall approach of interconnected energy systems, the coupling research between MILD combustion and various new combustion technologies should be promoted, especially strengthening the research on the co-combustion characteristics of coal powder, biomass and hydrogen, ammonia and other combustible gases, and assisting in energy transformation. Exploring the characteristics of turbulent two-phase flow, turbulent interphase heat transfer, and turbulent chemical coupling in the powder MILD combustion is crucial for deepening the understanding of powder MILD combustion. It involves multivariate analysis and high-precision simulation, which will be the focus and difficulty of future research.

The safe, green, efficient and low-carbon coal mining is the common goal of surface coal mines around the world. The development intensity and ecological carrying capacity of surface coal mine resources in China show the reverse development characteristics, and the vulnerable ecological environment areas in northwest China have become the main surface coal production areas, which makes surface coal mining and ecological environment protection become important scientific problems, ecological problems and development problems to be solved urgently. On the basis of the development situation, natural conditions and main influencing factors of surface coal mines, the connotation characteristics and overall structure of realizing the safe-green-efficiency-low-carbon mining of surface coal mines were explained. Aiming at the characteristics of the whole life cycle of pre-mining, mid-mining and post-mining of surface coal mines, in terms of four levels: safe mining technology, green mining technology, efficient mining technology and low-carbon mining technology, this paper puts forward eight key technologies including the time-limited slope control technology, the intelligent early warning decision-making technology, the new mode of transportation link, the ecological construction of mining area, the coordinated mining of adjacent mines, the intelligent mining design, the application of electric mining trucks and the ecological damage reduction at mining sources. The key work and direction of safe-green-high efficiency-low carbon cooperative mining in surface coal mines are clarified. In terms of the measures of safety-green-efficiency-low carbon co-development, regarding strengthening a top-level design, accelerating the distributed implementation, enhancing key researches, promoting personnel training, and improving standards and regulations, the paper proposes the target tasks to be accomplished in different stages in 2025, 2030 and 2035. In the new era, surface coal mines should firmly follow the development path of safe-green-high efficiency-low carbon, and realizes the high-quality development goal of surface coal mines.

Coal mining machine is the core equipment of completely automated working face, and the research and development of intelligent coal mining robot is crucial for achieving the intellectualization of fully mechanized working face. This paper comprehensively analyzes the current research status of sensing detection, position and attitude control, speed control, cutting trajectory planning, and tracking control in the coal mining machine roboticization process, and proposes five key technologies that must be solved in the development of intelligent shearer robots, including sensing and detection, pose control, velocity control, cutting trajectory planning and tracking control. Aiming at the problem of intelligent perception, this paper proposes the construction thought of a coal mining robot intelligent perception system, as well as the architecture of a coal mining robot intelligent per-ception system. The architecture of the intelligent perception system for coal mining robots is outlined, enabling a comprehensive sensing of running state, posture, environment, and so on, thereby ensuring the safe and reliable operation of intelligent coal mining robots. In terms of the position and attitude control problem of intelligent coal mining robots, the intelligent PID position and attitude control thought is proposed, along with an improved genetic algorithm-based PID pose control method, enabling precise pose control for the coal mining robot. As to the problem of velocity control, the thought of cutting load measurement based on the fusion of “force-electricity” heterogeneous data is proposed. Additionally, a neural network-based algorithm for cutting load measurement is presented, achieving an accurate load measurement. Furthermore, a traction and cutting speed adaptive control approach is proposed, including an artificial intelligence-based decision-making method for traction and cutting speed and a sliding mode control method for traction and cutting speed with disturbance rejection. This approach enables a precise and adaptive speed control for the coal mining robot. Regarding the problem of cutting trajectory planning and tracking control, the precise cutting trajectory planning thought is proposed, incorporating geological data and historical cutting data into a cutting trajectory planning model. The precise cutting trajectory tracking control thought is proposed, and an intelligent interpolation algorithm-based cutting trajectory tracking control method is given, achieving a high-precision trajectory planning and accurate tracking control for the coal mining robot. Considering the “position-attitude-velocity” collaborative control problem, the intelligent optimization idea of "position-attitude-velocity" collaborative control parameters is proposed, which utilizes an improved particle swarm optimization method based on multi-system constraints to optimize the coordinated control parameters, resulting in intelligent and efficient operation of the coal mining robot. The in-depth investigation of these five key technologies for intelligent coal mining robot provides some valuable insights for accelerating the development of high-performance, efficient, and reliable intelligent coal mining robot.

In view of the intelligentization of coal mine roadway excavation, this paper discusses the current development status of four major categories of intelligent fast excavation equipment, including continuous mining machine, excavation and anchor machine, full-section excavation system, and anchor excavation machine, analyzes the applicability of the four major categories of intelligent fast excavation equipment with the geological conditions, proposes some key technological issues for the realization of intelligent coal mine excavation which need to be resolved, and also explores the information transmission and intelligent analysis technology, intelligent perception technology, precise positioning and navigation technology, autonomous stereotyped directional cutting technology, remote and autonomous cutting control technology of road-header and multi-level and multi-process intelligent cooperative control technology, as they are the basis for the realization of intelligent roadway excavation. Based on the key technological issues needed to be solved in the mine roadway excavation under the complex geological conditions, the paper puts forward the design method of systematic analysis, modular design and optimal combination of functions, according to the functional requirements of the excavation operation and the requirements of the excavation process. A multi-level digital twin architecture of virtual control and virtual-reality combination is studied based on the multi-dimensional information reproduction of heading equipment, environment, and geological structure to realize the remote control of road-heading machine. A control method that integrates single-machine intelligence, system synergism, and synergism of underground intelligent control and surface remote monitoring is proposed. A new type of flexible advance support technology without repetitive crushing, multi-stage telescopic cutting technology of cutting section, and multi-rig parallel operation technology of intelligent anchoring unit have been developed, and a new type of combined unit for rapid roadway heading operation with a parallel operation of excavating, supporting, anchoring, transporting, and exploring processes has been also developed, and a flexible parallel operation technology of excavation robot, advance support robot, anchoring robot, and auxiliary transportation robot group has been proposed. A data-driven multi-machine, multi-process collaborative control behavior planning and decision-making method is proposed. In addition, it is proposed to construct a complete coal mine underground cross-system full-temporal-spatial information digital sensing system, build a data sensing intelligent monitoring platform with multi-parameter, multi-scale and full-temporal-spatial characteristics, that integrates the production state of underground site, spatial information of roadway, state of heading equipment, and risk information, etc., and realize a real-time communication between virtual system and actual tunneling system, so as to realize the intelligent and less-manned heading through data-driven planning and analysis.

The safety in the coal-producing mines in China is continuously improving, but coal and gas outburst accidents still occur. The prediction of coal and gas outbursts allows the scientific application of outburst prevention measures, which can ensure the safe coal mining to a certain extent. Machine learning is an interdisciplinary field involving probability theory, statistics, and computer science, which can explore the nonlinear relationship between outburst accidents and its associated indicators. The application of machine learning in coal and gas outburst prediction has received relatively widespread attention, and with the rapid progress of artificial intelligence and computer technology, it will play a greater role in the field of outburst prediction. Therefore, this paper provides a comprehensive review of the research on machine learning in coal and gas outburst prediction, analyzes the difficulties in outburst prediction and prospects its development direction. Firstly, the paper provides a brief overview of the research status on the hypothesis, occurrence mechanism, and prediction index selection of coal and gas outbursts. Then, it summarizes the research progress in the field of outburst prediction, including the application of support vector machines, neural networks, extreme learning machines, and ensemble learning algorithms. In addition, it also points out the existing problems in the current research, such as imbalanced samples, missing data indicators, and small sample sizes. Finally, the paper gives an outlook on the developments of coal and gas outburst prediction based on machine learning, including improving algorithm performance, optimizing feature engineering, and increasing sample size. With the continuous improvement of computer performance, more powerful models may be proposed, which can further improve the prediction accuracy of outburst accidents.

The fragile ecological environment in the western coal mining areas of China, compounded by intensive mining activities, has led to water and soil erosion, soil degradation, and damaged root systems. With a low plant water use efficiency, the ecological restoration becomes challenging, making the improvement of water use efficiency a key aspect in the ecological restoration or reconstruction of western mining areas. Soil water is a critical factor limiting the ecological restoration of arid and semi-arid coal mining areas, as it connects atmospheric water, surface water, groundwater, and vegetation growth, serving as an important carrier for water circulation and nutrient transport. Efficient and rational utilization of soil water is crucial to the success of ecological restoration. Therefore, investigating plant root water utilization strategies plays a significant role in the ecological restoration of western coal mining areas. This paper analyzes the main research methods of plant water use at home and abroad, compares the advantages and disadvantages of different methods, and reviews the corresponding research progress. In the damaged ecological environments of arid and semi-arid coal mining areas, the application of plant-microbe combined microbial remediation technology can improve plant water use efficiency and enhance plant water use strategies. At the same time, the microbial inoculation reduces the proportion of water absorption by plants from shallow soil layers, effectively increasing the absorption and utilization of water from deep soil layers by plants, thereby enhancing plant water use efficiency. This enables the inoculated plants to exhibit a higher ecological adaptability in the arid and semi-arid coal mining areas. This paper analyzes the current research progress and existing problems of plant water use in the western coal mining areas, discusses the improvement of water use strategies through microbial remediation in mining areas, and proposes the impact of different plant combinations on water use strategies and their research focuses in the ecological restoration of western arid coal mining areas. This lays a solid foundation for achieving green, sustainable, and high-quality development in the arid and semi-arid coal mining areas, and has important ecological application value.

The first and currently only Jurassic coal seam mining floor Baotashan sandstone water inrush and well flooding accident occurred in the New Shanghai No. 1 Coal Mine in Shanghai Miao Mining Area, Inner Mongolia. This paper researched the water inrush risk assessment method and prevention and control technology of the Baotashan sandstone in the Jurassic coal seam mining floor, which is highly water-rich. Firstly, it is clear that the water inrush source of the "11.25" accident is the Baotashan sandstone aquifer in the lower part of the Jurassic Yan'an formation, and the water barrier between the coal seam and the floor Baotashan sandstone has the characteristics of low strength, low softening coefficient and poor cementation, so it belongs to geological soft rock. Secondly, a water inrush evaluation system was established using “aquifer thickness, aquifer water richness, aquifer permeability, aquifer water pressure and the effective thickness of the 18 coal floor aquifer” as the main indicators, and the water inrush of the Baotashan sandstone aquifer was the dangerous zones are divided into three types: safety zone (32.21%), threat zone (37.53%) and dangerous zone (30.26%), and the accuracy of the evaluation model was verified through the “11.25” water inrush accident. Finally, combined with the engineering geological characteristics of the floor aquifer, the method of “fault grouting to form a local restricted boundary+group hole water release” was used to prevent and control Baotashan sandstone water inrush. It was set that “Water drainage begins until drilling site #1 exits work, the 2#, 3#, and 4# drilling fields continue the water drainage work until 3# exits work, and the 2# and 4# drilling sites continue to drain water until the model is replenished and balanced.” According to the specification, the maximum curtain permeability coefficient after grouting is 2×10−2 m/d, When the curtain permeability coefficient after fault grouting is 2×10−2 − 2×10−8 m/d, the drainage volume is 4.02×10−4 m3 − 3.478×10−4 m3. The proportion of safe areas in the mining area is 43.34%−67.37% respectively. Combining the grouting cost, drained water volume and safe area, when the curtain permeability coefficient is not greater than 2×10−4 m/d, can effectively ensure the safety and technical and economic benefits of the mine. The combined technology of fault grouting local restriction boundary+water drainage can effectively prevent and control sandstone water damage in Baotashan. The research work in this paper is of great significance and engineering practice value for the prevention and control of floor water in the Jurassic Coalfield development in western China.

Fractured soft and low permeability coalbed is commonly developed in China, which restricts the increase of single well gas production and industrial development of coalbed methane (CBM). Indirect fracturing is a kind of fracturing method to communicate with coal seams by creating vertical fractures in the neighboring layers and thus achieve effective coal seam transformation, which can solve disadvantages such as drilling collapse, coal dust production, fracturing fluid filtration loss and thin coal seam thickness. In this paper, physical simulation experiments and extended finite element numerical simulation analysis of indirect fracturing are used to reveal the factors influencing the fracture expansion of indirect fracturing in the coal seam roof and to clarify the fracture expansion mechanism in order to provide guidance for indirect fracturing technology. The indirect fracturing experiments under the influence of direct fracturing of coal seam and different fracture initiation location, vertical stress and construction displacement show that high fracture initiation pressure is more likely to produce long fractures, and the influence of primary fractures is significantly reduced; however, the farther the fracture initiation point is from the coal seam, the more energy is required for fracture initiation, and high fracture pressure will cause crushing damage to the coal seam; under large construction displacement, the fracture initiation pressure is correspondingly increased, the fracture initiation time becomes shorter, and the influence of primary fractures becomes smaller. The degree of impact of primary fracture becomes smaller. Under the condition of model parameter setting in this paper，the numerical simulation results considering the parameters of ground stress, fracture initiation location, rock mechanics and construction displacement show that the maximum horizontal principal stress and vertical stress difference is 3 MPa, and the combination of coal and roof elastic modulus difference

Data governance capability is fundamental to coal mine intelligence construction. It could accelerate the intelligent construction of coal mines and promote the digital transformation of the coal industry so as to building a modern energy system in digital China. This paper therefore discusses the theory and methods of improving data governance capability for intelligent coal mines. Specifically, this study analyzes its strategic demands of intelligent coal mine construction on data governance and offers a working definition for data governance capability for intelligent coal mines. Then an evaluative system is proposed for the evaluation of data governance capability for intelligent coal mines. Further, by drawing on capability maturity theory, this study establishes a maturity model that specifies the improvement path of data governance capability for intelligent coal mines. Finally, based on the PDCA cycle theory, this paper puts forward strategies for improving data governance capability for intelligent coal mines, in order to 1)supplement existing theories of data governance capability enhancement, and 2)provide references for future practices of data governance.

This paper aims to establish a model that can reasonably reflect the mechanical properties of coal containing gas under different water content and confining pressure conditions. Firstly, the stress-strain characteristics of coal containing gas under different water content and confining pressure conditions are analyzed based on triaxial tests. Afterwards, this paper obtains the Duncan-Chang model parameters by combining the Duncan-Chang model and Janbu formula. Moreover, it establishes the fitting formulas of initial elastic modulus failure stress and various influencing factors, and conducts an improved Duncan-Chang model to characterize the deformation law of coal containing gas under different stress levels. Finally, this paper verifies the improved model and evaluate the accuracy of the mode. The results show that the increase of water content is an important reason for the dynamic change of coal model parameters of coal containing gas. The prediction curve of the improved model is in good agreement with the actual test curve, and the improved model can accurately reflect the stress-strain characteristics of coal containing gas under different confining pressures and water contents.

This paper mainly discusses the development status, pain points and future trend of China’s coal mine robot industry. In the context of the “robot +” era, this paper expounds the development of China’s robot industry from the aspects of the number of robot enterprises, regional distribution, industrial park construction, advantage track, national policy, etc., and expounds the changes and challenges brought by the domestic Internet and manufacturing enterprises. This paper focuses on the analysis of coal mine robot technology and industry pain points, and extracts three major capabilities that coal mine robot should have to realize intelligence. Strengthening the construction of supply chain and standard system is proposed. The classification standard of coal mine robot L0-L5 is introduced in detail.

The goaf roadways have problems of high surrounding rock stress and large deformation under the conditions of hard roof and wide coal pillars in thick coal seams. In order to solve the above problems, this paper takes the 16403 fully mechanized mining face of Laoshidan Coal Mine as the engineering research background. The paper theoretically analyzes the influencing factors of large deformation of goaf roadways from the perspective of lateral fracture structure of wide coal pillar roof. The numerical simulation method is used to study the implementation of different roof cutting and pressure relief schemes for 16402 transportation roadway. The stress transmission law of the lateral roof of the 16403 return airway near the goaf during mining is studied. The hydraulic fracturing drilling is carried out on site for roof cutting and pressure relief to achieve deformation control of the surrounding rock of the goaf roadway. The research results indicate that the fracture structure of 'cantilever beam in low hard rock layer+masonry beam in high hard rock layer' is the main reason for the large deformation of the wide coal pillar in the goaf roadway of the extra thick coal seam. The roof cutting and pressure relief technology can be used to destroy the lateral fracture structure of the wide coal pillar roof to control the large deformation of the surrounding rock in the goaf roadway. The change in roof cutting angle can cause a change in the length of key block B. The larger the roof cutting angle, the smaller the length of key block B. The degree of load transfer from the lateral roof of the goaf side to the coal pillar is weaker, and the mining stress borne by the surrounding rock of the goaf roadway is smaller. When the roof cutting angle is 100°, the vertical stress and deformation of the surrounding rock of the goaf roadway are the smallest. After hydraulic fracturing drilling is carried out at a roof cutting angle of 100° in the 16402 transportation roadway, the deformation of the roof and floor of the 16403 return air roadway is reduced by 86.5% compared to the 16402 return air roadway without roof cutting pressure relief. The deformation of the two sides is reduced by 87.1%. The stability of the surrounding rock of the goaf roadway is greatly improved.

How to realize safe and efficient intelligent mining of rock burst coal seam is an important industrial technical problem. This paper systematically analyzes the distribution characteristics, mining status and development trend of rock burst mine in China, and deeply analyzes the main mining problems faced by rock burst mine. From the aspects of regional ground stress monitoring and inversion, mine development layout optimization, coal pillar size optimization, combined depressurization up and down well, displacement and filling mining, separated layer grouting, etc., the development status of rock burst mine life cycle prevention and control technology is described. In view of the difficult problem of roadway rock burst prevention and control, the collaborative intelligent adaptive anti-impact support technology and equipment for all roadways with rock burst are developed. The energy absorption anti-impact hydraulic support is used to achieve the effect of strong support for roadway surrounding rock under normal condition and rapid displacement and energy absorption during the impact process. Based on intelligent migration device of support, monitoring and warning system of support and intelligent design method of all roadway collaborative adaptive anti-impact support, the prevention and control system of intelligent energy absorption support of roadway under rock burst is constructed. This paper analyzes the anti-shock principle of the intelligent mining system of coal face, proposes to predict and warn the location and probability of rock burst by monitoring and analyzing the mining stress of surrounding rock and the fracture structure of overlying rock, based on 3D geological model and big data algorithm, etc., and carry out intelligent linkage control on the supporting posture and supporting force of hydraulic support and the cutting speed of shearer through the intelligent mining system. Realize the intelligent mining of coal face and the intelligent prevention and control of rock burst. From the aspects of intelligent monitoring of stope stress and overburden structure, construction of rock burst disaster database, classification prediction and early warning of rock burst disaster, this paper analyzes the research and development focus of intelligent rock burst prevention and control technology, and puts forward the composition and overall structure of mine rock burst monitoring and early warning system. From the aspects of top-level design, key technology, intelligent and accurate crisis relief and effect evaluation, the technical path and research and development direction of realizing safe and efficient intelligent mining of coal seam with rock burst in China are put forward.

This is an essay in the field of mining engineering. In the current new energy development strategy under the new situation, lithium is an indispensable key raw material to support the development of the new energy vehicle industry and promote the new energy revolution. It is positioned as one of China's 24 national strategic mineral resources, and its strategic position is extremely important. The safety of lithium resources and the continuous supply of lithium mineral products are related to the healthy and stable development of many industries and the national economy in China. China is rich in lithium resources. However as the world's largest consumer of lithium resources and producer of lithium batteries, lithium is highly dependent on foreign countries, and there are hidden dangers in the supply system. It is urgent to improve the safety and security of China's lithium resources. Based on the combing and research on the distribution of lithium resources at home and abroad and the supply and demand situation of lithium mineral products, this paper analyzes and elaborates on the main problems and causes faced by China's lithium resources. This paper analyzes the main problems faced by China's lithium resources and their causes, and puts forward opinions and suggestions on the development and utilization, scientific and technological research, industrial structure, institutional mechanism, personnel construction, market regulation, overseas strategy and other aspects in order to increase production of lithium resources and maintain supply and stability, which provides useful reference for ensuring the safety and stability of China's lithium resources and the healthy and orderly development of lithium mining industry.

According to the limiting factors of vertical shaft blasting construction and explosive controlled conditions, combined with the characteristics of the existing cutting technology, this paper puts forward the carbon dioxide two-step cylindrical cut blasting technology. First of all , this paper introduce the principle of carbon dioxide blasting technology and the structure of carbon dioxide blasting device ,expounds the core idea of two-step cylindrical cut.“two-step” refers to a description of the cut form from two dimensions of “time and space”. The rock in the cut area is divided into two steps with different depths, and the blasting sequence of the cut hole is divided into two different stages. At the same time, the cut hole is arranged into two rings with different diameters of the double cylinder shape, the center of the cut ring is arranged with a empty hole, the first-order cut hole in the inner ring, while the second-order cut hole in the outer ring, two cut holes are inclined to the center hole at a certain Angle, so that the top area of the cylinder is large and the bottom area is small. The first-order cut hole is blasting first, and the second-order cut hole is blasting later. This two-step cylindrical cut fully combines the advantages of “two-step” and “cylindrical cutting”, that the center hole provides weak free surface and compensation space for the blasting hole, while the first-order and the second-order cut hole are surrounded by a double cylinder.In this case the blasting is carried out in two stages, which effectively combines the shallow blasting and deep blasting, reduces the clamping force of the rock during the second blasting, expands the area of cutting cavity, and improves the blasting effect. Secondly, by analyse the principle of two-step cylindrical cut blasting technology, and deduce the shear resistance formula of cut blasting and the dynamic formula of blasting cavity，and determine the basic conditions for rock ejection from the cavity under the static action of carbon dioxide explosion gas.At last, by comparing the field application effects of dynamite straight cut blasting and carbon dioxide two-step cut blasting, indicate that the two methods have small difference in the three post-detonation indicators of circulating drill footage, hole utilization rate and cut cavity volume, which further proves that the carbon dioxide two-step cylindrical cut blasting technology is suitable for vertical shaft drilling. It provides a new technical way for vertical shaft cut blasting.

At present, intelligent coal caving in high gas fully mechanized top coal caving face is facing many problems, mainly including poor recognition accuracy of coal gangue, incomplete control research on coal flow and gas concentration, cumbersome design and development of follow-up process, and slow response of control system.In order to solve these problems, this paper developed a cloud side collaborative intelligent coal caving control system based on 5G communication.The system includes 5G network, cloud server, edge processor, terminal execution equipment, etc.It has a high data transmission speed, control response speed and data processing capability.Based on the analysis of fully mechanized coal caving process parameters and intelligent coal caving process flow, elaborates the four key technologies of intelligent coal caving the coal gangue identification technology, big block coal identification and coal flow load balance technology, gas safety linkage control technology, and digital twin technology of coal caving following machine.The application test was carried out in Baode 81309 fully mechanized top coal caving face.After the intelligent fully mechanized top coal caving technology was adopted, the top coal recovery rate increased from 86% to 93%, the coal gangue rate decreased from 21% to 15%, the total production efficiency increased by 10%, and the number of coal caving operators decreased from 3 to 4 to 1 to 2.The cloud edge collaborative intelligent coal caving control system based on 5G communication developed in this paper and its key technologies can also be extended to other fully mechanized coal caving faces, which is of great value for reducing personnel and increasing efficiency and safe and efficient mining of coal mines.

The real-time monitoring and tracking system of mine moving targets is an essential part of the construction of smart mines. The appearance of downhole inspection robots can realize the real-time monitoring of operators, but the existence of uneven lighting, coal dust interference and other factors lead to the traditional image detection algorithm can not accurately detect operators. Based on this, this paper proposes an improved YOLOv5s and DeepSORT algorithm for downhole personnel detection and tracking that can be deployed in downhole inspection robots. Firstly, the data set was made by using the video recorded by the surveillance camera and inspection robot, and then the improved YOLOv5s network was used to identify the underground personnel: Considering that the detection and tracking algorithm for downhole personnel contains complex network structure and huge parameter volume, which limits the response speed of the detection model, this paper uses an improved lightweight network ShuffleNetV2 to replace the original YOLOv5s backbone network CSP-Darknet53. Meanwhile, in order to reduce the interference of complex image background and improve the attention of operators, Transformer self-attention module is integrated into the ShuffleNetV2. Secondly, the FPN+PAN structure in Neck is replaced by BiFPN structure in order to effectively fuse multi-scale features and effectively transmit inference information. Then, improved DeepSORT was used to encode and track personnel: considering that the underground environment was dark, with low illumination and no texture, it was difficult for DeepSORT to effectively extract personnel's appearance information, so DeepSORT's small and medium residual network was replaced by deeper convolution to enhance DeepSORT's appearance information extraction ability. Finally, the improved algorithm is verified by open pedestrian data set and self-built underground personnel detection and tracking data set. The results show that compared with the original YOLOv5s model, the average detection accuracy of the improved detection model is increased by 5.2%, the number of parameters is reduced by 41%, and the speed is increased by 21%. The improved YOLOv5s-DeepSORT downhole personnel tracking method has a precision of 89.17% and a speed of 67FPS, which can be effectively deployed in downhole inspection robots to realize real-time detection and tracking of operators.

Currently, algorithms such as support vector machine (SVM) and random forest (RF) are less applied in the field of coal mine roadway support. The paper studies the applicability of different machine learning models for support parameter design.Thus a higher performance model would be established to achieve reasonable and scientific design of anchor bolt support. Firstly, it is suggested to establish an intelligent prediction database for coal mine roadway support. Through on-site research, questionnaire survey, and literature search, the coal mine roadway samples are collected. The data is processed using methods such as filling in missing values, modifying outliers in box charts, and removing local abnormal factors to establish a coal roadway support database. The paper proposes a coal roadway support parameter prediction model based on synthetic minority oversampling technique (SMOTE) - genetic algorithm (GA) - SVM. The data in the database is divided into training and testing sets. The SMOTE technology is used to balance training samples, and improve the model's fitting capability for minority class samples. The training process uses GA to globally optimize the hyperparameters of SVM, further improving the overall performance of the model. The test results show that the classificaton precision of the SMOTE-GA-SVM model reaches 83.8%, which is 21.8% higher than the traditional SVM model. The machine learning methods such as SVM, artificial neural network (ANN), RF, AdaBoost (ADA), and naive Bayesian classifier (NBC) are introduced into the prediction of coal roadway anchor support parameters. The corresponding support parameter prediction models are established. The comparison results showed that the best to worst prediction models are ranked as SMOTE-GA-SVM, RF, GA-ANN, SVM, NBC, and ADA, with an average classificaton precision of 69.9%. The result verifies the feasibility of machine learning methods in predicting the parameters of coal roadway bolt support. The SMOTE-GA-SVM model is applied in Shanxi Huobaoganhe Coal Mine Co., Ltd., with a precision of 87.5% and strong applicability and reliability.

The central and western coal resources have the highest degree of enrichment and superior development conditions in China. With the improvement of mining efficiency, the disturbance of high-intensity and large-mining-height mining mode to groundwater system also increases. In particular, the groundwater in the aquifer outside the disturbance range of the water-conducting fracture zone gradually participates in the mine water inflow process during the coal mining. Such mode leads to a series of problems such as large deviation of mine water inflow prediction, inaccurate evaluation of water inflow risk and unclear water hazard prevention measures, which brings great hidden risks to the current mine water hazard prevention and control. In this paper, a derivative mode of dynamic water inrush is summarized. With the coal mining, the evolution of groundwater system caused by overburden failure will induce new disaster sources, resulting in different forms of water inrush. Its connotation is to change the basis of defining the derivative dynamic water inrush model from the traditional static analysis before mining to the dynamic evaluation considering the change in the whole mining cycle. The derived dynamic water inrush model of the mine can be preliminarily divided into three categories, namely, “skylight leakage type”, “bed separation disaster type” and “channel permeability increase type”. This paper mainly discusses the derivative dynamic water inrush mode of “skylight leakage type”. Taking the Shanxi Yushen mining area, a shallow buried coal seam mining area with high strength and large mining height, as an example, the disaster-pregnant conditions of “skylight supply type” derivative disasters are discussed in depth. Through supplementary analysis of water-richness and hydraulic connection strength of indirect water-filled aquifer, the comprehensive evaluation of water inrush risk in roof aquifer is achieved, and the evaluation method system of disaster derivative model is put forward. Through the transformation of mining mode, the active prevention and control system is constructed. A passive prevention and control system is constructed by multi-objective advance drainage before mining and local grouting after mining. By further refining the mine water inrush disaster model, optimizing the evaluation system and establishing comprehensive prevention and control technology, it provides a scientific basis for the protection of groundwater resources and safe low-carbon mining in ecologically fragile areas.

The fully mechanized mining face adopting pre-driven recovery room is prone to large roof deformation at the final mining stage, which will lead to support crushing accidents. Based on the three main roof failure forms after longwall face entered recovery room, this paper established different mechanical models for roof sag of the recovery room. By analyzing energy release and work process in roof deformation, this paper obtained the immediate roof sag of recovery room under different main roof failure forms. Taking the large roof deformation and support crushing accident of recovery room in the N14201 longwall face of Zhangjiamao Coal Mine as example for analysis, this paper analyzed the influencing factors of the models and found that the main roof break position, the thickness of key block and its overlying strata, the rotation angle of key block and the supporting intensity have significant impact on the roof sag of recovery room. The research results confirmed that the reason for the support crushing accident in N14201 longwall face of Zhangjiamao Coal Mine: the main roof is broken within 4~6 m above the protective coal pillar, and the main key stratum is broken and unstable due to the mining of upper 3-1 coal seam.

High-voltage electric pulse(HVEP)drilling has become a new and efficient rock breaking method, which is also the research focus in the field of drilling speed increase. To probe into rock breaking mechanism of high voltage electric pulse, this study establishes a two-dimensional numerical model of multi-physical field coupling electric breakdown of single pair of electrodes. The model reproduces the generation of plasma channels in homogeneous red sandstone from the coupling of current field, electric breakdown field and circuit field. This paper analyzes the effect of electrode pair angle, voltage and electrode spacing on rock electrical breakdown(that is, the formation of plasma channel in rock). The model includes the circuit structure parameters of pulse tool, the occurrence and development of electrical breakdown, and the relationship between electrical breakdown intensity and time. Results indicate that the plasma channel begins to sprout from the partial area near the top of the discharge electrode and develops towards the partial weak dielectric strength. With the voltage value of loading pulse increasing gradually, the time of electrical breakdown decreases gradually; comparatively, the equivalent failure volume of rock model increases gradually, and there is a positive correlation between them. On the precondition that the rock can be electrically broken, increasing the electrode spacing can improve the rock breaking efficiency of high voltage electric pulse. The equivalent failure volume of rock shows significant fluctuations during the gradual increase of electrode inclination angle of discharge electrode, and its extreme value mostly appears in the range of electrode inclination angle of 35°~ 55°. To further promote the industrial application of high-voltage electric pulse rock breaking, this paper proposes a three-dimensional numerical model of multi-physical field coupling dynamic electric breakdown of red sandstone based on two-dimensional model, reproducing the appearance of the fracture crater in the rock during the rock breaking process with electrode bit. At the same time, the self-designed coaxial electrode bit is selected for experiments of electric breakdown, and the laboratory experimental results of electric breakdown confirm the simulation experimental results.

In order to scientifically evaluate the impact risk of steeply inclined extra-thick coal seam in folded area and provide theoretical guidance for the prevention and control of rock burst, a numerical model including folds is established in this paper based on the prevention and control of rock burst in south mining area of Wudong Coal Mine. With the help of multiple linear regression and CASRock engineering software, the back analysis of ground stress field of steeply-inclined extra-thick coal seam in folded area of Wudong Mine is carried out. Taking B1+2 coal seam as the research object, the stress data in coal seam, roof and floor are extracted, the stress-cover depth variation curve is plotted, the distribution characteristics of pre-mining stress field are explored, and the risk assessment index related to pre-mining stress is determined. According to the back analysis data of in-situ stress and previous research results, the evaluation indexes of burst risk are determined from the aspects of geological factors and mining conditions. The static weights of 7 geological factors and 5 mining conditions are obtained by Analytic Hierarchy Process. By substituting the static weight into the dynamic weight calculation formula and combining with the traditional comprehensive index method, the risk assessment of B1+2 panel at +500 m level in the south area of Wudong Mine is carried out. According to the rockburst risk classification table, the burst risk of this panel is medium, which is consistent with the conclusion of the geological report, and the rationality of the method was verified. This method is used to estimate the burst risk of coal seam with different depths. Control group is chosen, using the traditional comprehensive risk index method to evaluate the burst of the same area, the results show that the method to obtain the risk ratings were higher than the traditional methods, approach of this paper highlights the risk factors in the evaluation index, overcoming the other indicators evaluation error caused by the interference factors.

It has always been a common demand to stay away from the harsh environment with narrow space, numerous devices, complex operation process, and hidden hazards, and realize intelligent unmanned mining in the coal industry. To achieve this goal, it is very necessary for us to develop an effective theory of vision computing for underground coalmine applications. Its main task is to build effective models or frameworks for perceiving, describing, recognizing and understanding the environment of underground coalmine, and let intelligent equipment get 3D environment information in coalmine from images or videos. To effectively develop this theory and make it better for intelligent development of coalmine, this paper first analyzed the similarities and differences about computer vision and visual computing in coalmine, and proposed its composition architecture. And then, this paper introduced in detail the key technologies involved in visual computing in coalmine including visual perception and light field computing, feature extraction and feature description, semantic learning and vision understanding, 3D vision reconstruction, and sense computing integration and edge intelligence, which is followed by typical application cases of visual computing in coalmines. Finally, the development trend and prospect of underground visual computing in coalmine was given. In this section, this paper focused on concluding the key challenges and introducing two valuable applications including coalmine Augmented Reality/Mixed Reality and parallel intelligent mining. With the breakthrough of underground vision computing, it will play a more and more important role in the intelligent development of coal mines.

Ultra wideband (UWB) radar life detection technology has the advantages of low power consumption, good penetration, and high confidentiality. It is beneficial for improving the survival rate of trapped personnel after disasters. This paper systematically summarizes the research progress and current status of UWB radar life detection technology both domestically and internationally. According to the different forms of transmitted signals, UWB radar life detection technology is divided into continuous wave radar life detection technology and pulse wave radar life detection technology. The principles and application advantages of the two detection technologies are introduced respectively. Based on the respective features of continuous wave radar life detection technology and pulse wave radar life detection technology, this paper analyzes the key technologies of UWB radar life detection from three perspectives: detection signal transmission, echo signal preprocessing, and life signal extraction and analysis, and summarizes the research status of the three key technologies. The paper proposes prospects for the research on UWB radar life detection technology. The technology breaks through the hardware performance of life detector transceivers, improves the transmission signal bandwidth, and optimizes RF power amplification technology to increase the detection distance through walls. The technology comprehensively utilizes multiple feature extraction methods and intelligent pattern classification methods, as well as new generation information technologies such as artificial intelligence, big data, and cloud computing, to improve the precision of target recognition. The technology develops a human target recognition and positioning equipment based on multi input multi output radar and a high-precision distributed networked fully polarized UWB radar life detector to enhance the dimension of detection results.

Insulation is considered the weakest link in electrical equipment. The combined effects of special working conditions in coal mines and aging factors such as electrical, thermal, and mechanical stresses make it difficult to determine the aging mechanism and evaluate the condition of EPDM insulation for high-voltage cables used in mines. This paper introduces the basic performance and aging factor types of EPDM insulation for high-voltage mobile flexible cables used in coal mines. Based on the physical, chemical, mechanical, and electrical properties of EPDM under the influence of multiple aging factors, the aging mechanism of EPDM is proposed. This paper summarizes the basic principles and existing problems of online monitoring methods for insulation resistance, partial discharge, dielectric loss factor, and temperature of mining high-voltage cables. The paper summarizes the current research status of insulation status evaluation methods for mining high-voltage cables. The paper introduces the evaluation methods for insulation status of multi parameter based on improved radar map and single parameter based on dielectric loss mining high-voltage cables. To cope with the development of coal mine intelligence, on the one hand, it is suggested to do research on intelligent perception and control of mining electrical equipment to compensate for the lack of state perception and state evaluation feature quantities. On the other hand, it is necessary to study lightweight models or algorithms to reduce the computational complexity, parameter quantity, and analysis time of intelligent terminals near devices. It improves the feasibility of state evaluation technology, and lays the foundation for achieving intelligent analysis and decision-making.

The in-situ monitoring technology for overburden movement in mining has the features of adapting to complex geological conditions in deep shaft high pressure water and thick coal seam mining, multi layer dynamic monitoring, and high-precision remote real-time online transmission. It provides effective data support for mining enterprises to carry out roof disaster prevention and control. Starting from the practical background of coal mining application, this paper systematically reviews the development process, technological progress, and application effects of in-situ monitoring technology for overburden movement in mining. Based on the development history of mining pressure theory and overburden movement monitoring technology in China, this paper comprehensively introduces the important stages of in-situ monitoring technology for overburden movement in mining. It elaborates on the theoretical innovation and technological breakthroughs achieved by this technology in three aspects: multidimensional real-time collaborative monitoring, unmanned online monitoring, and deep rock movement monitoring. Based on the monitoring engineering examples of coal mines such as Bulianta Coal Mine, Tongxin Coal Mine, and Gaojiabao Coal Mine, the effectiveness of in-situ monitoring technology for overburden movement in mining is demonstrated in practical engineering applications. The application prospects of this technology in different types of mining areas and research fields are discussed. It is pointed out that the development trend of in-situ monitoring technology for overburden movement in mining is precision, intelligence, and integration, namely optimizing sensor performance and layout plans to improve monitoring precision and accuracy, using artificial intelligence, big data, and Internet of things technology to achieve automatic analysis and prediction, combining the in-situ monitoring technology with other technologies to form a complete monitoring system.

5G technology is the foundation for achieving intelligent mining construction. In response to the problem of difficult interoperability between mining 5G intelligent terminals and control platforms among different manufacturers, it is necessary to unify and standardize the data exchange and sharing process in the 5G system. The deployment architecture of '5G+intelligent mining' is proposed. The mining 5G intelligent terminals can interact and share data with servers containing control platforms through 5G base stations, switches, and 5G core networks in coal mines. This paper introduces the message types, message transmission formats, message composition, and message connection methods transmitted in the mining 5G system. For specific application scenarios in the mining field, the data in the mining 5G system is divided into voice data, video data, sensor data, and control data. The data types transmitted by the mining 5G intelligent terminal in different application scenarios are provided. This paper analyzes the basic transmission capabilities that mining 5G intelligent terminals and control platforms should have to meet data interaction. It is pointed out that the process of data interaction between mining 5G intelligent terminals and control platforms includes device information query and reporting, device upgrade, log collection, alarm issuance and processing, and platform configuration issuance and processing. It proposes the participating entities, security levels, and processes for data sharing of mining 5G intelligent terminals (including data aggregation, application, authorization, provision, and feedback). By implementing standardized processes, while ensuring communication reliability, the data exchange and sharing process under the '5G+intelligent mine' system architecture has been simplified to accelerate the intelligent construction of mines.

This is an essay in the field of mining engineering. Deep-sea rare earth rich deposit, as a potential rare earth resource, are an important supplement to land rare earth resources and may become one of the first deep-sea minerals to be exploited. In this paper, four deep-sea REE rich deposit (REE rich deposits in the western Pacific Ocean, the southeast Pacific Ocean, the middle and east Pacific Ocean, and the Middle Indian Ocean basin-Wharton Basin.) are analyzed. This paper summarizes the basic resource characteristics of deep-sea rare earth rich deposit (such as large total reserves, large distribution differences, and the main occurrence mineral is biological apatite), and reviews two methods (acid leaching-extraction separation technology and separation-flotation method) used in the separation and extraction of deep-sea REE. The result shows that the acid leaching-extraction separation technology has the disadvantages of low recovery of REE and excessive acid consumption. The separation of sediment samples before flotation operation can achieve efficient enrichment of REE in deposit under the condition of low acid consumption, which is an important development direction to separate and extract REE resources from deep-sea REE rich deposit. Based on this, it is suggested to strengthen the research and development related to efficient classification of deep-sea REE rich deposit resources and in-situ mining and leaching technology in the future.

This is an essay in the field of mining engineering, which takes Panxi vanadium-titanium magnetite associated sulfur resources as the research object, and expounds its comprehensive utilization path and its low-carbon development significance. Sulfur is one of the typical associated elements of Panxi vanadium-titanium magnetite, and it is also a port element of the emerging industrial chain of food-resource-energy in the double carbon era. Based on the endowment conditions of Panxi vanadium-titanium-magnetite associated resources and the occurrence status of sulfur minerals, this paper analyzes the current situation and characteristics of associated sulfur resources, and uses the mining and dressing industry chain of vanadium-titanium magnetite to discuss the possible environmental impact of sulfur in the process of comprehensive utilization. The comprehensive utilization potential analysis is discussed from two aspects of mineral product demand and comprehensive utilization maturity risk assessment. Under the circumstances that associated sulfur resources are facing the challenge of green and low-carbon development, this paper puts forward comprehensive utilization suggestions from the three aspects of planning top-level design, technical research, and production line promotion, aiming to promote the development of the sulfur industry guided by the principle of green and low-carbon, Focus on promoting carbon reduction and pollution reduction through source sulfur selection production line intervention. The research in this paper can provide new ideas and specific suggestions for the comprehensive utilization of sulfur resources associated with vanadium-titanium magnetite, environmental planning and low-carbon development.

Under mining conditions, the micro crack structure of the composite strata of the coal seam floor affects the uplift and seepage of the groundwater in the underlying high water pressure aquifer, and its complexity is of great significance for the prediction and early warning of the water disaster in the coal seam floor. In this paper, a total of 57 groups of rock samples extracted from three adjacent mines in the east of Pingdingshan Coalfield are taken as the object. Based on the comprehensive information of SEM image acquisition and N2 adsorption test, the fissure ratio of rock stratum area, equivalent crack diameter of rock stratum, fractal dimension value of fissure area, specific surface area, crevice volume and its fractal dimension are the main controlling factors. Using entropy weighted TOPSIS mathematical model, the complexity of the micro fracture structure of the composite rock stratum between the Ji16-17 coal seam and the Cambrian limestone top interface is quantitatively evaluated. The results show that the micro crack structure of the composite strata in the floor of the Ji16-17 coal seam is very simple, simple, medium, complex and extremely complex, accounting for 25.00%, 21.43%, 39.29%, 7.14% and 7.14% respectively. The micro crack structure of the composite strata in the study section is relatively uncomplicated; Compared with the four rock sections, the order of the quantitative mean value of the complexity of the rock stratum micro fracture structure is: L1−L2 limestone section>L5−L7 limestone section>sandstone section>bauxite mudstone section. The complexity of the rock stratum micro fracture structure better reflects the development of the rock stratum fracture. The paper considers the coupling effect of multiple factors on the composite rock stratum, realizes the quantitative classification and zoning discrimination of the micro crack structure in the vertical section of the composite rock stratum, which is of great significance for accurately describing the aquifer performance of the composite rock stratum in the coal seam floor and scientifically guiding the prevention and control of the water hazard in the coal seam floor.

The existing mine pressure prediction models are mostly single prediction models that rely on fixed length time series features. It is difficult to accurately capture the composite features of mine pressure time series data, which affects the accuracy of mine pressure prediction. To solve this problem, an ensemble learning mine pressure prediction method based on variable time series shift Transformer-long short-time memory (LSTM) is proposed. Based on the Laida criterion and Lagrange polynomial method, the outlier values in the mine pressure monitoring data are eliminated, and the missing values are inserted. Then normalized preprocessing is performed. The paper proposes a variable time series shift strategy to divide mine pressure time series data at different scales. It avoids potential data shift issues that may exist in fixed length time series. On this basis, the ensemble learning mine pressure prediction model based on Transformer-LSTM is constructed. By combining the attention mechanism and the accurate time series feature representation capability, the dynamic features of the mine pressure change law are captured at multiple levels. The voting algorithm of ensemble learning is used to jointly predict the mine pressure data to overcome the limitations of a single prediction model. The experimental results show that the voting algorithm of ensemble learning can reduce the volatility of mean absolute error (MAE) and root mean square error (RMSE) of mine pressure prediction. It effectively reduces the sensitivity impact of different scale feature series to the mine pressure prediction results. Compared with the Transformer model, the MAE of the Transformer-LSTM model's prediction results on two roof mine pressure datasets of fully mechanized working faces improves by 8.9% and 9.5% respectively, and the RMSE has increased by 12.7% and 16.5% respectively. The above indexes are also higher than those of back propagation (BP) neural network model and LSTM model. The method proposed in the paper effectively improves the accuracy of mine pressure prediction.

Mine communication is an indispensable part of the intelligent development of coal mines. This paper analyzes the advantages and disadvantages of different communication systems and technologies in different development stages of wireless communication in underground coal mines. It is concluded that 5G and WiFi6 currently have significant technological advantages and good applicability in terms of transmission rate, delay, reliability, and user capacity. They are the mainstream solutions for mine wireless communication technology in recent years. This paper discusses the problems in underground wireless communication system construction and the corresponding development directions. ① Technological convergence issues. Different scenarios have different requirements for bandwidth, delay, power consumption and reliability. A single communication technology can not meet the requirements of all application scenarios in coal mines. It is necessary to select appropriate communication technology according to the actual application situation to meet the application requirements. Different technologies are integrated through protocol converters, gateways and other devices to form an integrated communication network platform for technological convergence above the ground and underground. ② System integration issues. Since each system is provided by different manufacturers, and the communication protocol and hardware interface are inconsistent, it is difficult to truly realize the data sharing of each system in the mine. It is necessary to provide standard interfaces, open network architecture, and unified user data to provide interconnection and inter-working functions for monitoring, emergency, production, and other systems. It is further required to provide unified data messages to enable data transmission with low delay, high concurrency, real-time, and synchronization within each system. ③ Device power consumption issues. The existing mine 5G base station and other equipment can only be made into a single flameproof product due to their high power consumption. The equipment is bulky, large, and difficult to install and maintain, which restricts the popularization of 5G technology in coal mine. Low-power design can be started from the main chip, RF module, and power amplifier module.

While giving full play to the role of coal energy security supply, it is an important proposition related to national energy security and overall development to realize green and safe mining and clean and low-carbon utilization of coal resources. This paper analyzes the influence of changes in the international development environment on the China’s utilization of oil and gas resources in the international market, and studies the rigid demand for energy supply in China. Based on the current situation of energy development and utilization with coal as the main energy source in China and following the fundamental requirements of building a harmonious modernization between man and nature, this paper puts forward the green and low-carbon development direction and path of coal industry in the process of realizing the goal of “dual carbon”. ① China’s external dependence on oil and gas resources exceeds 70% and 40% respectively, and its strategic reserves are insufficient. Under the background of profound changes in the international situation, the uncertainty of using oil and gas resources in the international market increases, and the external risks of national energy security have increased. ② Building a modern country will inevitably lead to the rigid growth of energy demand. At present, it is difficult for new energy sources to replace fossil energy safely and effectively, and the main energy position of fossil energy will be difficult to change in the short term. ③ Comparing with the “dual carbon” goal, the proportion of coal consumption before the peak shows a continuous downward trend, and the total consumption will usher in an inflection point. After the peak, the main energy position of coal will be weakened, but the role of strategic mineral resources and coal-based raw materials will be further highlighted. ④ Driven by the goal of “dual carbon”, the basic national conditions with coal as the main energy source determine that coal will continue to undertake the important mission of energy security supply and further play the role of strategic mineral resource as raw material. However, the high carbon resource attribute of coal determines that the development and utilization of coal will face the dual pressures of ensuring supply and reducing carbon emissions. Therefore, in order to serve the high-quality economic and social development, which requires security and green and low-carbon energy supply, it must be based on the current characteristics of energy production and supply with coal as the main energy source and new energy as the supplement at this stage, and take the new progress of ecological civilization construction as the fundamental principle. The research on the key technologies should be enhanced such as the technologies of coal mining and ecological carbon sink, CO2 geological storage in deep coal seams and coal mined-out areas, and collaborative development and utilization of new energy in coal mining areas, which will support the high-quality development of the China's coal industry with technological innovation under the goal of “dual carbon”.

CBM reservoir is a typical fracture-controlled gas reservoir, and the scale of fracturing and fracture-filling effect have decisive control on gas well productivity. In order to reveal the influence mechanism of the hydraulic fracturing effect of CBM vertical wells on the productivity effect of gas wells, taking the Haishiwan Mining Area of Yaojie, Gansu as an example, this paper focuses on reporting the fracturing effect of coal reservoirs under the form of vertical well development and its understanding of the constraints on productivity. the result shows: ① The fracture pressure of CBM well mainly feeds back the characteristics of the wellbore cement sheath rather than the mechanical properties of the coal reservoir. From the fracturing curve of this well, the fracture pressure is not obvious, indicating that the thickness of the cement sheath in the wellbore annulus is moderate, and the cement sheath is relatively easy to rupture during hydraulic fracturing. The energy of the injected fracturing fluid is mainly used to prop up the coal cracks; ② It can be seen from the fracturing curve that the propagation pressure of the hydraulic fractures(HF) in this well is relatively high, indicating that the structure of coal reservoir is relatively fragmented and coal fines are developed. In addition, there are multiple wave morphological features in the fracture propagation stage of the fracturing curve, indicating that multiple secondary fractures are propped up. On the whole, the HF in this well are relatively complex, and it is speculated that branched secondary fractures develop on both sides of the main HF. ③ Serious sand plugging occurred after sand injection in this well. The main reason was that the fracturing fluid in the coal reservoir was lost due to the loss of the fracturing fluid in the near-wellbore area, resulting in the formation of wedges by proppant de-sanding in the HF, which made subsequent proppant injection difficult. It is related to the coal fines of primary fractures and the development of a small amount of tectonic coal fines; ④ The fracturing microseismic monitoring data show that the main HF of the coal reservoir in this well are NE 50°, and the coal rock microseismic events are more active in the northeast direction, indicating that the natural fracture (NF) of the coal reservoir is more developed in this direction; Based on the observation results of fracturing and mineback, this paper proposes a division plan for the effective propped area, the actual fracture area and the rock mass disturbance area of HF. It is believed that the actual half-length of the HF in the coal reservoir of this well is less than 20 m, the half-length of the effectively propped HF is less than 5 m, and The small amount of fracturing fluid injected, the formation of wedges by proppant de-sanding induced by fracturing fluid-loss, and the sand plugging caused by coal fines accumulation are the main factors for the short fractures in the coal reservoir of this well; ⑤ Combined with the law of coalbed methane productivity, it is considered that the gas reservoir management and drainage system in this well is reasonable,However, the effective propped HF in the coal reservoir are too short, and the coal fines migration in the coal reservoir leads to the rapid decline of the conductivity of the near-well HF, which is the key restricting mechanism for the productivity of gas wells.It is recommended to increase the injection volume of fracturing fluid, appropriately increase the flow rate of fracturing fluid, reduce the proppant-sand ratio, and focus on controlling fracturing fluid leak-off and the formation of screenout wedges in the hydraulic fracturing of coal reservoirs in the later stage.The coal seam in this area has a large burial depth and high stress, and the realization of large-scale fracture propped is the key to coal reservoir fracturing. Meanwhile, the reservoir is dry and the fracturing fluid is seriously leak-off, the CO2 pre-fracturing test can be carried out.

The utilization of underground space in abandoned mines is a key direction supported by the coal industry. By combining underground space utilization, flood storage, and heat supply in winter, this paper proposes a comprehensive utilization model of flood storage and heat extraction in the abandoned mine, based on three technologies: ground flood diversion, underground flood storage and heat pump. This paper addresses the concept, key technologies and scientific issues of the model. The distribution of abandoned mines in China and its relationship with precipitation distribution were analyzed. The potential for flood and energy storage in abandoned mine was also studied. Results showed that 13 provinces, including Anhui, Henan, and Shandong province, can utilize approximately 60 million cubic meters of underground space and store nearly 6 volumes of West Lake water, making it suitable for engineering demonstration of flood storage and heat extraction in abandoned mines. Among them, five abandoned mines in Huainan mining area can utilize approximately 300 000 cubic meters of underground space, with energy storage capacity of up to 94 500 GJ that can meet the heating demand of 210 000 square meters. Taking Qishan Mine as an example, a scheme was designed based on ground flood diversion and storage, underground water storage, and mine water extraction and utilization. According to preliminary calculations, the heating power of Qishan Mine can reach 6 835 kW which can provide heating for 136 700 square meters of buildings, reduce carbon dioxide emissions by about 5 330 tons, and save 3.507 5 million yuan. This demonstrates the feasibility of flood and energy storage in abandoned underground space. Research showed that the comprehensive utilization model of flood storage, energy storage, and heat extraction in abandoned mines can not only effectively utilize the underground space of abandoned mines but also alleviate local flood disasters during the flood season. It can develop low-grade clean energy in mine water and has certain significance in improving the added value of underground space utilization in abandoned mines and promoting the utilization of underground space in abandoned mines.

As a device for timely rescue after disasters, life detectors play an irreplaceable role in locating, exploring, and searching for living organisms. This paper analyzes the working principles, technical features, usage scenarios, advantages and disadvantages of the currently used life detectors. The detectors include radar life detectors, audio life detectors, infrared life detectors, and other types of life detectors. Combined with practical applications, this paper points out the problems of the above life detectors. ① The detection technology is single and the comprehensive integration is low. ② The detection methods are traditional and equipment intelligence is insufficient. ③ The parts of the detector are not standardized, making equipment maintenance difficult. ④ Some life detectors have a relatively large structure and are inconvenient to carry, which affects rescue efficiency. In response to the existing shortcomings and problems, the development trends of life detectors are proposed. ① It is suggested to improve the integration level of life detectors. It is suggested to design life detection devices that use multi-source fusion to collect information, and use multiple information sources to obtain and detect life information. ② It is suggested to improve the intelligence level of life detectors, give them partial autonomy in decision-making, and reduce errors in life detection caused by improper operation by operators. ③ It is suggested to design modular life detectors and develop relevant standard procedures to standardize the components of the same type of life detector. It will reduce the difficulty of repair and maintenance of life detectors. ④ It is suggested to improve the circuit board design precision of the life detector, fully utilize spatial structure, reduce volume and improve portability without reducing the functionality of the life detector.

Currently, the intelligent construction of coal mines is in a transitional exploration period from primary to intermediate and advanced intelligence. The independent innovation capability of existing intelligent equipment still needs to be strengthened. The core technologies are bottleneck problems. The reliability problem under complex underground storage conditions is prominent. It is of great significance to use the new generation of information technology to promote the digital transformation and upgrading of coal mine equipment, and to promote safe, efficient, and green coal mining through digitization and intelligence. This paper reviews the evolution process of intelligent development of coal mining technology and equipment in China. This paper analyzes the production characteristics of each stage of coal mining. It is considered that the coal mine intelligence has completely changed the coal production mode. The production factors are mainly intelligent equipment, intelligent systems, and compound technical talents. They have essentially improved the level of safe and efficient production of coal mines, and helped the coal mines to reduce personnel, increase safety and improve efficiency. Among them, intelligent coal mine equipment is the core element of coal mine intelligence. Considering the demand for the digital and intelligent transformation and development of future coal mine equipment, we have explored the path of integrating the new generation of information technology and coal mine equipment. It uses equipment as an intelligent carrier. It endows the equipment with humanized intelligent capabilities such as intelligent perception and analysis, intelligent judgment and reasoning, intelligent decision-making and control, intelligent diagnosis and learning through the new generation of information technology. The system architecture of the Internet of things, 5G, big data, cloud computing, and artificial intelligence technology enabling intelligent perception, intelligent transmission, intelligent analysis, intelligent computing and intelligent decision-making of coal mine equipment has been constructed. The paper analyzes the theoretical, technical, and talent challenges in the development of digital intelligence in coal mining equipment. The paper proposes suggestions for the development of digital intelligence in coal mining equipment. Consolidating the foundation is the priority. It is necessary to build a top-level design theoretical system for intelligent coal mining equipment, strengthen key core technology research, accelerate the construction of new infrastructure, and consolidate the foundation of intelligent coal mining development. The intelligent technology for coal mining equipment and special application scenarios in coal mines develop in collaboration and coupling. It is suggested to meet the on-site needs of coal mines, form the intelligent technology for coal mine specific scenarios, and explore innovative models of equipment digital intelligence integration. The intelligent technology and green mining technology integrate and develop. It is suggested to create digital, intelligent, and green equipment. It is suggested to develop new models of intelligent, efficient, and low-carbon coal mining, and promote energy conservation and consumption reduction in coal production. It is suggested to establish a sound system for cultivating intelligent talents in coal mines, cultivate interdisciplinary and composite talents, and enhance talent reserves for the construction of intelligent coal mines.

The conveyor belt and driving device are the main components of the belt conveyor and are the high-risk areas for faults. Taking conveyor belt faults and driving device faults as the starting point, this paper analyzes the mechanisms of conveyor belt deviation, slipping, damage, stacking and scattering, as well as the faults of the driving device roller, idler and reducer. It focuses on the research progress of knowledge-driven and data-driven fault diagnosis methods for belt conveyors. Based on the knowledge processing technology, the knowledge-driven method realizes the unification of symbol processing and numerical processing, the unification of reasoning process and algorithm process. It mainly includes expert system and fault tree analysis. The data-driven method uses machine learning and data mining techniques to analyze and process historical data. It establishes diagnostic models, and achieves fault diagnosis purposes. It mainly includes support vector machines (SVM), comparison method, and diagnosis methods based on sound and vision. This paper analyzes the current challenges and future development trend of belt conveyor fault diagnosis methods. ① The historical fault data and real-time data should be combined to infer equipment health. The early minor faults should be predicted so as to remind the staff to carry out predictive maintenance. ② The correlation between coupling faults of belt conveyors should be revealed. The emerging technologies such as artificial intelligence should be used to study joint diagnosis methods for coupling faults. ③ The multimodal machine learning technology should be utilized to study the mechanism of multimodal information fusion and utilization of belt conveyors. Fault diagnosis methods for multimodal information fusion of belt conveyors needs to develop. ④ The fault knowledge graph and the belt conveyor domain knowledge should be combined to realize the belt conveyor equipment fault tracking and fault early warning. Through the knowledge query, knowledge reasoning and auxiliary decision-making functions, the capability of fault handling and precise mining of potential fault risks of equipment can be improved.

Mine air stopping is a key facility separating production systems from abandoned ones. Ensuring full lifecycle risk management is of great significance for ensuring safe production. Based on the current status of comprehensive control technology for mine air stopping, the shortcomings of the existing air stopping management mode are analyzed from two aspects: static attribute information management and dynamic information monitoring. The paper puts forward the concept of intelligent management and control in the full lifecycle of air stopping. It indicates the overall construction path of air stopping risk monitoring and early warning based on big data strategy of the Internet of Things (IoT)+Artificial Intelligence (AI)+Cloud Platform (CP), and integrated with cloud-edge architecture. The IoT platform is applied to access digital monitoring and linkage control equipment for air stopping units, achieving transparency in the full lifecycle control of air stopping. The method focuses on the evolution signs of air stopping information and efficient edge computing. It deploys mobile terminals, edge computers and other field terminals to adapt to online prediction and advance warning of air stopping service status. In the smart cloud, the virtual reality scenario of a distributed mine air stopping and its full lifecycle evolution characteristics are reconstructed iteratively in real time with multi-source fused information and digital twin models at the core. The paper analyzes key theories and and model construction methods, including the physical-digital driving mode of evolution information in air stopping environments, the multi-source heterogeneous data fusion model of air stopping perception information, the edge detection and hierarchical intelligent warning of air stopping anomalies, and the emergency intelligent decision-making and collaborative prevention and control throughout the entire lifecycle of air stopping. The physical and functional architecture of an air stopping full lifecycle safety risk monitoring and warning system based on the IoT is designed. The on-site embedded air stopping multi-parameter integrated monitoring sensors and supporting intelligent hosts are developed. The early sensing and monitoring and warning methods for air stopping risks are proposed to achieve digital empowerment and effectively promote the construction of smart mines.

This paper reviews the general situation of the development and innovation practice of China's coal industry in the past 50 years promoted and witnessed by the Journal of Mine Automation from coal mine mechanization to automation and intelligence. This paper expounds on the innovation process of coal mine automation and intelligence. It focuses on the analysis of the research and development and practice of coal mine information infrastructure, automation and intelligent equipment and systems. The integration and unified hosting of heterogeneous networks is the information foundation for coal mine automation and intelligence. On the basis of the continuous maturity of the heterogeneous network of the backbone network and access network, the wired communication transmission rate has reached over 10 Gibit/s. The wireless communication technologies such as 5G and WiFi6 have been widely applied, providing a reliable communication platform for the intelligent construction of coal mines. Wired communication, wireless communication, IP broadcasting, personnel locaiton monitoring system, and video monitoring system are integrated to build a multi-network integrated communication system, achieving integrated carrier network and unified location service. The development of intelligent automation equipment in coal mines is rapid. It explores adaptive cutting technology based on transparent geology, automatic coal release control technology on the basis of technologies such as memory cutting of coal mining machines and automatic following and moving of hydraulic brackets at coal mining working face. On the basis of achieving profiling cutting, positioning navigation, and remote control, the excavation working face has made breakthroughs in technologies such as drilling anchor integration, multi-machine collaboration, and cutting template planning of roadheader based on geological model, achieving good results. The development of intelligent equipment for coal flow transportation systems is supported by intelligent variable frequency energy-saving transmission. The integrated research and application of coal mine robots are achieved. The mature application of inspection robots is obtained. The breakthroughs in intelligent auxiliary operation robots are achieved. The development of a multi-scene robot cluster scheduling and command system forms a robot cluster. The automation and intelligent construction of coal mines have officially entered the stage of intelligent mine comprehensive control from single system automation, comprehensive mine automation, and the Internet of Things. The realization of intelligent perception, intelligent self-control, high-speed transmission, collaborative control, and intelligent decision-making is an inevitable requirement for the development of intelligence. The paper proposes key directions for the iterative development of coal mine intelligent technology, including the establishment of high-precision transparent geological models, the normal and reliable operation of unmanned operating systems, the construction of intelligent compatibility and collaboration mechanisms for coal mine giant systems, the intelligent collaborative control of the entire process of 'excavation, mining, transportation, washing, and sales', and the optimization of a flexible coal production and supply system.

This paper introduces the evolution and development process of coal fire and its features. This paper expounds on the detection mechanism and research progress of four layers of space exploration technology divided according to the different spatial positions of detectors. The technologies include underground, surface, aerial, and aerospace detection methods. The paper analyzes the advantages and disadvantages of the above four detection technologies. The existing research problems are pointed out. ① The detection precision is insufficient and it is difficult to accurately delineate the acquisition range. ② The detection technology is outdated, and it is difficult to accurately detect high-temperature points in fire areas. ③ The detection method is single and cannot accurately determine the specific information of underground coal fire combustion. In view of the new features of underground coal fire, such as concealment, coupling and complexity, the development directions of underground coal fire detection technology are proposed. ① The detection instrument data needs to be finely processed, so as to improve the sensitivity of magnetic difference to temperature, the detection precision of the resistivity method, the feature extraction rate and the result precision of the infrared detection method. ② It is suggested to utilize high-tech equipment to serve coal fire detection technology. ③ It is suggested to improve the collaborative utilization of multi-level detection technology. Firstly, large-scale fire detection is carried out using the four th level aerospace remote sensing technology to obtain the basic spatial distribution features of underground coal fire anomalies. Secondly, further exploration is carried out using the third level aerial remote sensing detection technology to obtain the specific spatial distribution of underground coal fires. Finally, a more detailed distribution of high-temperature points in the coal field fire area is obtained by using the surface detection technology and underground detection technology at the second level and the first level to supply and verify. ④ It is suggested to develop 3D visual and dynamic monitoring and early warning of coal field fire areas. 3D inversion and joint inversion imaging are performed by use of data from four different levels of detection technology. Based on the imaging results, visual monitoring and early warning of coal fire development and spread are carried out, so as to achieve active prevention and control of underground coal fine disasters.

The existing wireless communication technologies in wireless blind spot coverage have challenges in non-line-of-sight scenarios in coal mines. In order to solve the above problems, a solution approach is proposed to introduce intelligent reflecting surface (IRS) into the wireless communication system in coal mines to achieve blind compensation of wireless signal coverage. This paper analyzes the causes of wireless coverage blind spots in coal mines, including closed mine environments characteristics, common non-line-of-sight scenarios, and safety constraints on transmission power and antenna settings. However, traditional wireless coverage blind spot solutions for underground coal mines have limitations in hardware deployment, maintenance costs, and technical implementation. They cannot truly meet safe and efficient communication needs of specific mining scenarios. IRS has significant performance advantages in achieving coverage blind compensation due to its low cost, low power consumption, easy deployment, and scalability. This paper introduces IRS technology from three aspects: hardware structure, auxiliary channel model and typical application scenarios (precise positioning, signal and energy simultaneous transmission, UAV communication, edge computing and physical layer security). This paper proposes the use of IRS technology to optimize underground wireless blind spot coverage. By deploying IRS reasonably in coal mines, it reduces the absorption and scattering of main signal components by walls, and utilizes the adjustable reflection characteristics of IRS to optimize signal propagation. It significantly improves signal strength and coverage range. The future research directions of IRS technology in underground wireless communication in coal mines are pointed out. The directions include energy management of IRS-aided coverage and blind compensation systems, IRS-aided underground communication based on artificial intelligence, application of new IRS technology, and flexible deployment of IRS.

This paper analyzes the technologies of mine ranging and positioning, such as ultrasound, laser, video, inertial navigation, pedometer, and radio. Among them, radio ranging and positioning have the advantages of long positioning distance, small positioning error, no impact from light, little impact from dust, easy identification, and low system cos. They are suitable for positioning mine personnel and precise positioning of mine personnel. The paper analyzes radio ranging and positioning technologies such as UWB, ZigBee, RFID, 5G and WiFi6. Mining UWB has the advantages of long positioning distance, small positioning error, and low cost. It is suitable for precise positioning systems for mine personnel. Mining ZigBee has the advantages of long positioning distance, small positioning error, and low cost. It is suitable for mine personnel positioning systems. Mining RFID has the advantage of having the lowest system cost. It is suitable for coal mine underground personnel management systems. The positioning precision of mine 5G and WiFi6 is lower than UWB, and the system cost is higher than ZigBee. It is unsuitable for mine personnel positioning and precise positioning systems. The received signal strength indication (RSSI), time of arrival (TOA), time differences of arrival (TDOA), two-way ranging (TWR), symmetrical double-sided two way ranging (SDS-TWR), angle of arrival (AOA) and other mine personnel positioning algorithms are analyzed. The RSSI positioning method has a large positioning error, making it difficult to meet the needs of mine personnel positioning and precise positioning. The TOA positioning method requires accurate and synchronized timing between the positioning card and the substation clock. The positioning card and substation have high costs. It is unsuitable for mine personnel positioning and precise positioning. The TDOA positioning method does not require synchronization between the positioning card and the positioning sub-station clock. It has low requirements for the precision of the positioning card clock and low cost of the positioning card. However, it requires accurate timing of the positioning sub-station clock and synchronization between the positioning sub-stations. The positioning substation cost is high. It can be used for mine personnel positioning and precise positioning. The TWR positioning method and SDS-TWR positioning method do not require clock synchronization between the positioning substation and the positioning card, nor do they require clock synchronization between the positioning substations, nor do they require clock synchronization between the positioning cards. This reduces the complexity and cost of the positioning card and the positioning substation. It is suitable for mine personnel positioning and precise positioning. The AOA positioning method system is complex, costly, with large long-distance positioning errors and dead angles. It can only be used for straight-line obstacle-free positioning. The positioning antenna and positioning precision are greatly affected by mechanical vibration. It is not suitable for the independent positioning of mine personnel and precise positioning. However, it can be used in conjunction with other mine positioning methods.

This is a paper in the field of metallurgical engineering. High-end titanium products, metallic titanium and chlorinated titanium dioxide, are of great strategic significance to economic development and national security.TiCl4 is an intermediate for the production of high-end titanium products. The main industrial production methods are molten salt chlorination and boiling chlorination. The titanium resources in our country contain high Ca and Mg impurities, which are more suitable for the production of TiCl4 by the molten salt chlorination method.However, there is a large amount of residue of molten salt chlorination generated, which has complex components and is difficult to be recycled. Direct discharge of those residue will pollute the environment and waste resources.This paper systematically analyzes the research status and development trends of comprehensive treatments of residue of molten salt chlorination at home and abroad.It is pointed out thatdeep burial and accumulation after lime neutralization treatment of residue of molten salt chlorination cannot solve the environmental pollution problem.The water solution treatment can specifically recover certain substances in the filtrate, but the amount of wastewater is large, and the removal of impurities is difficult. Additionally, the process flowsof those water solution treatmentsare always complicated, and there is no effective utilization of the filter residue. The non-water-soluble methods have unique development advantages, among which the method of high-temperature phase transformation is a promising treatment, which could recycle and utilize the residue of molten salt chlorination at high temperature without coolingand water dissolution, quite reducing the amount of wastewater, environmental pollution,and resources loss.

This is a paper in the field of metallurgical engineering. In this paper, natural clay mineral serpentine was subjected to mechanochemical activation (MA) for the highly-efficient removal of Ni (Ⅱ) in wastewater and simultaneous recovery of metal nickel as secondary resources. The effectiveness of serpentine for precipitation and recovery of Ni was investigated, with the process mechanism analyzed. The results showed MA of serpentine led to the disordering of the stable crystal structure of serpentine, thereby resulting in the release of large amounts of Mg2+ ions and hydroxyl group in aqueous solution, and the resultant interaction between Ni (Ⅱ) and OH-, with the formation of amorphous Ni(OH)2 as sediments. The maximum processing capacity of activated serpentine for Ni (Ⅱ) reached up to 226.04 mg/g, meanwhile the final Ni (Ⅱ) concentration met up with the national discharging standard, indicating the feasibility of remediation of heavy metal contaminations by a very low dosage of activated serpentine. Concluded from these results, mechanochemical activation can be expected to boost the reactivity of natural serpentine, thereby improving the utilization efficiency of low-cost serpentine for the clean-up of environment pollutions and recovery of metal resources, which is conducive to promoting the green development of mineral-resource-environment cross-fields.

This is a paper in the field of ceramic materials for metallurgy. Magnesia chrome refractory is widely used in copper industry due to its excellent high temperature strength, fine slag corrosion resistance and good performance. In this paper, the research status of corrosion mechanism of magnesia chrome refractories for copper metallurgy is summarized theoretically, and the effect and action mechanism of factors on the service life of metallurgical furnace was clarified, such as slag temperature, grade, Cr2O3 content and additives in magnesia chrome bricks. Finally, according to the research status, the main ways to improve the service life of magnesia chrome refractories are summarized, which will provide guidance and help for the structural design and performance control of magnesia chrome refractories in the future.

This is a paper in the field of mining engineering. With the increasing demands for energy conservation and consumption reduction in mineral processing plants, ball mill load measurement is the key technology to realize mill control and optimize the grinding process. This paper summarizes the measurement methods of mill load in the recent years: differential pressure method, grinding sound method, vibration method, power method, ultrasonic method, indirect detection method based on multi-source signal fusion. Moreover, it summarizes and analyzes the mill load modeling methods that have emerged inrecent years. In the future, the indirect methods of multi-source information fusion will still be the main methods to detect mill load, modeling methods based on improvement of neural network and new online detection methods, as well as the establishment of efficient and accurate load detection models will be the main development direction of mill load detection.

This is a paper in the field of ceramics and composites. High-temperature foaming method has been successfully applied to prepare foamed ceramics material by using steel slag and shale slag as the main raw materials. Silicon carbide and borax were used as the foaming agent and fluxing agent, respectively. This paper focused on the influence of steel slag content, SiC addition, borax addition and foaming temperature on the pore structure and properties of foamed ceramics. The experimental results showed that when the steel slag content is 20%, the shale slag is 80%, SiC of 0.5% and borax of 4% are additionally added, the foaming temperature is 1090 ℃ and the holding time is 40 min, the foamed ceramics material has the best properties. Under optimal conditions, the bulk density, compressive strength and thermal conductivity of the foamed ceramics are 0.468 g/cm3, 3.265 MPa and 0.121 W/(m·K), which meets the property requirements of building insulation materials. The main crystal phases are augite phase, quartz phase and diopside phase．

This is a paper in the field of metallurgical engineering. As a technical method to effectively improve the permeability of charge column and reduce the coke ratio, mixed charging of ore and coke is widely used to improve the forward process of blast furnace. In this paper, the reduction and migration behavior of vanadium at different temperatures in the mixed charging process of vanadium titanium ore and coke in blast furnace are studied. The results show that when the temperature is lower than 1350℃, the reduction condition of vanadium in the layer loading area is better than that in the mixed loading area; In the melting zone, vanadium is mainly concentrated at the interface between slag and iron; The formation of magnesium ferrite in the soft melt zone can promote the vanadium to gather near the molten iron, and the basic oxide MgO can promote the migration of V to Fe.

This is a paper in the field of mineral materials and environmental engineering. In this paper, cadmium-containing wastewater was used as the research object, and low-grade iron tailings loaded with chitosan was used as the adsorbent to compare the adsorption effect of low-grade iron tailings on Cd2+ before and after loading chitosan. The results showed that the adsorption effect of the composite adsorbent better than low-grade iron tailings adsorbent; At the same time, the Box-Behnken Design (BBD) response surface method is used to design the experiment, and the cadmium ion adsorption rate (Q) is used as the response value. The initial pH value, the amount of adsorbent added and the adsorption time are investigated. The three influencing factors have separate and interactive effects on the adsorption and removal of cadmium by chitosan loaded on low-grade iron tailings, and a nonlinear quadratic multiple regression prediction model of the influencing factors of low-grade iron tailings loaded with chitosan and cadmium ions is established: Q=86.16+14.68×A+5.21×B+1.36×C−1.98×A×B−1.54×A×C−0.46×B×C−6.75×A2+0.12×B2+1.25C2, and got the better optimizedexperimental conditions for adsorption. The results show that the primary and secondary order of the influencing factors of the composite adsorbent on the Cd2+ adsorption rate is initial pH value> adsorbent added amount> adsorption time. When the initial pH value is 8.00, the amount of adsorbent added is 25.00 g/L, the adsorption time is 15 min, the initial Cd2+ concentration is 30 mg/L, and the adsorption temperature is about 25 ℃, the predicted value of the maximum adsorption rate of Cd2+ is 99.33%, the experimental value is 99.16%, and the experimental value is basically the same as the predicted value, indicating that the model is reasonable for the Cd2+ adsorption optimization model and its optimization conditions are feasible.

This is a paper in the field of metallurgical engineering. Vanadium is a rare strategic metal resource in China, which is used in many fields and is closely related to the national economy. Nowadays, the comprehensive utilization value of vanadium extraction process is becoming more and more significant, and the solvent extraction method for vanadium extraction has attracted extensive attention because of its advantages of strong selectivity and high product purity. In this paper, the roasting, leaching, purification and enrichment and vanadium precipitation technology were reviewed. The research work and methods of vanadium separation by solvent extraction were summarized, and the extraction of vanadium by tertiary amine extraction agent and its development status at home and abroad were discussed emphatically.

This is a paper in the field of metallurgical engineering. Organophosphorus class extractant D2EHPA (P204) is very widely used in vanadium extraction. Firstly, the form of vanadium present in the leach solution affects the effect of extraction, V(IV) is mainly stable in solution in the form of VO2+ in a strongly acidic solution; when the pH value gradually increases, V(V) mostly exists in the form of H2V10O28 4- and HV10O28 5-. Secondly, based on the research of organophosphorus extractant P204 in recent years, this paper analyzes the conformational relationship of organophosphorus extractant P204 and finds that the spatial site resistance effect is equally important as a secondary factor compared with the type of phosphoryl adjacent groups, based on the hydrogen bonding effect, the extractant molecules will produce dimers or even multimers between them, thus changing the structure and properties of the extractant molecules. Finally, the progress of the development and application of P204 extractive vanadium and the outlook on the future of the related fields are presented, pointing out the future research directions of P204 extractive agents.

This is a paper in the field of process mineralogy. Daqiao gold mine is a super-large gold mine discovered in the Qinling region,but in the process of mining primary ore, it is found that the recovery rate of gold is very low by using the traditional beneficiation process, so the refractory pre-deposit is determined, this paper aims to investigate the occurrence state and refractory factors of gold in the deposit. Through microscopic identification, SEM, EPMA, and chemical analysis, combined with mineral processing tests, it is found that gold mainly exists in siliceous breccia in the form of natural gold and silver gold. The granularity of gold and gold-bearing minerals is very small, so that in the process of beneficiation,the sandal can not be dissociated to a high degree under the condition of very fine grinding granularity, which is the main reason that restricts the beneficiability of the ore deposit, it is also found that the ore contains more carbon, which is another reason restricting the ore beneficiability.

This is a paper in the field of process mineralogy. Dawudian crystalline graphite deposit is a extra large graphite deposit which located in the Langshan Mountain lying in the Bayan obo rift zone. To get some insight into the characteristics of Dawudian crystalline graphite deposit ore and its gangue minerals, this paper systematically studies the ore characteristics of Dawudian crystalline graphite deposit. Some modern analysis and testing methods were used. Such as X-ray diffraction analysis, rock ore identification, spectral semi quantitative analysis. The results show that: (1) The useful mineral of the ore is graphite, and the gangue minerals are mainly quartz, feldspar, muscovite, andalusite, pyrite, etc. (2) The maximum particle size of ore graphite flake is 2.5 ~ 3 mm, and the minimum is 0.001 mm, which is mostly concentrated between 0.01~0.05 mm. It is a fine flake microcrystalline graphite ore. (3) The fixed carbon grade of the main beneficial elements of the ore varies from 2.50% to 11.18%, generally from 3.00% to 7.00%, the average grade is 4.15%, the content of harmful components is 0.16%~4.23%, the content of P2O5 is 0.05%~0.79%, and the content of Fe2O3 is 3.89%~10.38%. The impurity minerals are mainly siliceous minerals and clay minerals. (4) The ore has no other comprehensive utilization value mineral except graphite.

This is a paper in the field of mining environmental engineering. Heavy metal pollution in soil has a long-time impact, with high biological toxicity and serious threat on human health. In order to study the present situation of soil heavy metal pollution in a lead-zinc mining area and assess its risk, a lead-zinc mining area was taken in Jiangxi as the study object, and the speciation contents of heavy metal elements (Cu, Pb, Zn, Cd) in the soil samples of a lead-zinc mining area were analyzed by themodified BCR successive extraction, and the correlation of heavy metal elements was studied. The environmental risk of heavy metal elements was evaluated by the method of risk assessment coding (RAC) and ratio of secondary phase and primary phase(RSP). The results showed that: The Cu, Zn, Cd and Pb elements in the soil of the lead-zinc mining area exceeded the standard, and the Cu, Zn and Pb elements were mainly in residual state. Compared with Cu, Zn and Pb, Cd element had a higher content of acid extractable state, and its bioavailability was strong, so the pollution of Cd element was serious. The residual-state contents of Cu, Zn and Pb in the soil samples of the mining area were significantly positively correlated with the total contents, while the residual-state contents of Cd were not significantly correlated with the total contents. The contents of Cu, Zn, Cd and Pb in the acid extractable state were significantly positively correlated, but the contents of acid extractable state was negatively correlated with pH value. The conclusion of risk assessment coding method and ratio method of secondary phase and primary phase was relatively consistent, which showed that the pollution of Cd element was serious with a high environmental risk, while that of Cu, Pb, Zn elements was relatively light with a low environmental risk. This paper is expected to provide reference for the prevention and control of soil heavy metal pollution in the lead-zinc mining area.

Coal seam mining causes deformation, fracture and migration of overlying rock, further leading to the surface subsidence and ecological damage, which are the main manifestations of mining damage.Quantitatively characterize mining damage is the key to analyzing the stability of surrounding rock, designing mining parameters, and the premising of roadway support parameters.According to the finite element and discrete element simulation methods commonly used at this stage, this paper proposes a quantitative index(damage degree)to characterize mining damage: the proportion of zone plastic volume and the proportion of contact fracture length(number).On this basis, this study carried out the optimization of high-intensity mining parameters of the western mining area, the stability analysis of the coal pillar under the condition of mining and water immersion, and the progressive damage characteristics analysis of the roadway surrounding rock in the water-filled fault structure area by using the damage degree index.The quantitative relationship between the damage degree of the overlying rock and the mining parameters is obtained, which can realize the reasonable optimization of the mining parameters.This paper revealed the progressive damage characteristics of mining water immersion in coal pillars.We deemed that there is a danger of water seepage in the mined-out area as a water storage area under the existing coal pillar conditions.This study quantified the damage distribution characteristics of the surrounding rock in the roadway in the water-filled fault structure area, and proposed the corresponding? solution of dredging the fault through the roof aquifer, grouting reinforcement of the original fault fracture and strengthening the support.By comparing with common indicators such as the height of the water-conducting fracture zone and the width of the plastic development of the coal pillar, this research found that the damage degree indicators are more sensitive to the characterization of mining damage, and could realize continuous mining damage characterization.

The study of the transient electromagnetic detection device with small sized coil and easy installation underground will offer new insights into the real-time dynamic exploration and forecast water-bearing structure in excavation roadway.By drawing on the full-space transient electromagnetic theory, this paper adopted the three-dimensional time-domain finite element method for numerical simulation to explore the characteristics of the secondary field response obtained by small coil excitation and the transient electromagnetic response received by the magnetic core coil.This study constructed a geological-geophysical model of the water-bearing fault in front of the roadway excavation working face, studied the transient electromagnetic response characteristics of the small coil device for the water-bearing fault, and compared the effects of small coil and conventional coil in advance detection.The study shows that : ①the decay law of the induced electric potential generated by the small coil source excitation is the same as that of the induced electric potential generated by the conventional transmitting coil with time, ②the magnetic core coil can effectively improve the induced signal strength, ③the application of both the small coil device and the conventional coil device can effectively explain the distribution range of the low resistance area, ④the detection results match the verification results of the roadway excavation.Combined with the underground field test, this paper verified the applicability and effectiveness of the small coil device applied to mine transient electromagnetic method advance detection.

This paper proposed a new method for the determination of chlorine in coal by Eschka's mixture decomposition-ion chromatography so as to satisfy the needs of determining chlorine content in coal samples in large batches in coal exploration, coal production and processing industries.Specifically, this paper improved the sample pretreatment steps and determined the experimental parameters.The detection limit of the method was 0.001 7 %, the relative standard deviations of ten parallel determinations of three actual coal samples were in the range of 1.08 % ~3.92 %, the recoveries of six spiked determinations were in the range of 98 % ~104 %, and the results of the three standard coal samples were all within the guaranteed values.Results showed that the detection limit of the method was lower than that of the national standard method, and the precision and accuracy met or exceeded the national standard method.The determination of chlorine in coal by Eschka's mixture decomposition-ion chromatography has the advantages of simple operation, low cost and high determination efficiency and could be widely applied in the batch determination of a large number of samples.

The intelligence of fully mechanized working face is a key link in the intelligence of coal mines. The perception and analysis of hydraulic support state is the premise and foundation of intelligent control of fully mechanized working face. The pressure and posture of hydraulic supports are key state data that can be directly monitored. The fusion analysis of the two is the basis for intelligent control and execution of hydraulic supports. Taking the pressure and posture of hydraulic supports as the research object, an state perception architecture for intelligent fully mechanized working face is introduced. The current status of hydraulic support pressure perception and analysis technology is summarized from two perspectives: hydraulic support stress and overlying rock pressure. It is pointed out that the current big data based mine pressure analysis has not been applied, the mine pressure and roadway pressure data at the working face have not been synchronously measured, the full face data analysis of the entire mining area has not been achieved, and there is insufficient attention paid to advanced hydraulic support. The paper elaborates on the principles and methods of hydraulic support posture perception, and summarizes the existing hydraulic support posture analysis methods. The necessity of pressure-posture fusion analysis for hydraulic support is analyzed. The existing methods for pressure-posture fusion analysis of hydraulic supports are summarized. The paper explores the development trend of hydraulic support state perception and analysis technology in fully mechanized working face. It is suggested to do in-depth research on big data technology, multidimensional data fusion perception and analysis technology, and digital twin technology in the application of hydraulic support state perception and analysis, so as to achieve the precise analysis of hydraulic support state data, intelligent control and decision-making.

Fully mechanized mining equipment is gradually becoming larger, more complex and more intelligent. The traditional equipment management methods of regular maintenance and post maintenance are no longer able to meet the high reliability requirements of equipment operation in coal mine intelligent construction. Therefore, studying the relevant theories and technologies of fully mechanized equipment health status assessment has great practical significance for coal mine intelligent mining. This paper proposes the scope definition of fully mechanized mining equipment health status assessment and the fully mechanized mining equipment health status assessment process. This paper summarizes the research status and development trends of comprehensive mining equipment health status assessment methods from four aspects: signal acquisition, feature extraction and fusion, health status level classification, and health status assessment model establishment. The current challenges faced by fully mechanized mining equipment health status assessment related technologies are analyzed from aspects such as signal acquisition and sensor optimization layout, data processing and feature extraction, establishment of health status assessment models, and application of fully mechanized mining equipment status assessment. In response to the current research status and challenges mentioned above, the development trend of fully mechanized mining equipment health status assessment technology is discussed from the aspects of improving data collection schemes and fault mechanism research methods, building high-performance big data computing platforms, establishing deep learning assessment models, researching dynamic evaluation models for fully mechanized mining equipment health status, and developing fully mechanized mining equipment health status assessment systems. It is pointed out that in the process of coal mine intelligence, it is necessary to ensure that the theoretical research, algorithm development, and engineering application of fully mechanized mining equipment health status assessment go hand in hand.

The deep integration of the coal industry and artificial intelligence (AI) is an important path for modern mines to achieve intelligent personnel reduction, cost reduction, and efficiency improvement. AI empowerment in the entire process and business application scenarios of the coal industry is a specific technical measure to achieve coal mine intelligence. In the context of the current development of intelligent coal mines, a basic paradigm for the evolution of primary intelligent coal mines to new generation intelligent coal mines has been proposed. The composition, functions, and technical connotations of primary intelligent coal mines and new generation intelligent coal mines have been compared and analyzed. It is pointed out the importance of AI empowerment technology for new generation intelligent coal mine and its two key applications and implementation: the coal mine industry mechanism AI model and the coal mine Industry internet platform. The paper summarizes the current research status of industrial mechanism AI models for complex operations such as coal mine geology, mining, excavation, and safety monitoring. The paper clarifies the rapid development trend of industrial mechanism AI analysis in intelligent coal mine construction. A new generation of intelligent coal mine multi-level cloud edge collaborative industrial Internet platform architecture is designed. Using industrial information software and hardware facilities such as group data center, mine data center, production system centralized control center, and combining the features of massive data cloud computing and small amount of data edge computing, a multi-level cloud edge collaborative mechanism of group cloud, mine cloud and link edge, scene edge is proposed. It is pointed out that further research directions in the future should continue to strengthen the development and software research of AI models for coal mining industry mechanisms. Gradually a knowledge software system empowered by AI throughout the entire process of coal mining will be formed. It is suggested to fully utilize the digital resources and information facilities of the coal mining industry Internet platform to gradually realize the AI technology support of the coal mining industry Internet platform.

In response to the current challenges of high water pressure and easy conduction in kilometer deep wells, we propose the “hydrophobic pressure reduction, slurry reinforcement” mine water control technology, which requires slurry materials with “high strength, strong stability, easy flow, low cost” and other properties. “High strength” can be achieved by adding nano-reinforced materials. “Strong stability” can be achieved by preferentially selecting easy-to-consolidate and difficult-to-disperse raw materials and adjusting the mixing conditions. “Stable flow” can be achieved by adjusting the particle size of added raw materials and increasing the interfacial friction. “Low cost” can be achieved by using existing large-scale industrial and mining solid waste products that are in urgent need of treatment, supplemented by a small amount of additives. In view of the above problems, this paper aims at reinforcing the coal seam floor with slurry, and takes the large-scale utilization of industrial and mining wastes as the direction. By using waste tire rubber particles, fly ash and clay as the main materials, supplemented with a small amount of admixtures, the orthogonal test method is used to carry out experimental research on the basic performance of solid waste slurry filling materials. The effects of different rubber particle admixtures and admixtures were analyzed in the paper, and their effects on the flowability, mechanical properties, stability in mine water environment, impermeability and microstructural properties of the grouted stone body were derived. The research results show that when rubber particles are mixed with 20%, fly ash with 65%, clay with 15%, and nano-silica with 1% of solid powder, the flow of the grouted slurry is 293 mm, the 28 d compressive strength of the grouted stone body is 11.7 MPa, and the seepage pressure of the stone body is 0.8 MPa, and the obtained test results can meet the demand of field grouting reinforcement, which is useful for The obtained test results can meet the demand for on-site grouting reinforcement, which has scientific reference value for large-scale bottom slab fracture grouting reinforcement and also provides reference for large-scale utilization of solid waste products.

The cutterhead was one of the key parts of the Tunneling Boring Machine to achieve tunnel mining. Cutterhead’s continuous breaking rock was the rock destruction process under the cutter group. The cutter of cutterhead was used as a direct tool for rock breaking, and the arrangement of the cutter would directly affect the breaking performance such as the force of cutter and energy consumption. This paper mainly explores the influence of cutter installation parameters on the rock breaking force and specific energy in the multi-cutter collaborative rock breaking mode. Firstly, the characteristics of rock breaking during the cutter excavation and the way of multi-cutter collaborative effects created by the adjacent cutter during the rotation are analyzed. Using the motion characteristics of multi-cutter around the center of the cutterhead rotation and slow penetrating into the rock on the cutterhead, a rock constitutive model including the cutter’s displacement loading method and the form suitable for simulating the damage of rock element in the excavation was established, a finite element model of three cutters rotary rock breaking for techniques such as rock failure separation criteria was introduced. This paper simulates the rock breaking process of multiple cutters spiral intrusion rocks. Then, the single-factor influence of three main cutterhead arrangement parameters, cutter spacing, cutter installation polar angle difference and cutting sequence, on the rock breaking performance indicators such as rock breaking force of cutter and specific energy is analyzed by finite element simulation calculation. Finally, an orthogonal experiment is designed to analyze the influence of the above parameters on the total force of rock breaking under the interaction of multiple factors. The results show that the cutter spacing and installation polar angle difference have the most significant influence on the rock breaking performance of the cutter under the cooperative breaking rock conditions. The cutter spacing affects the penetration of lateral cracks between adjacent cutting paths. With the increase of the tool spacing, the lateral crack penetration between adjacent cutting paths is gradually difficult, and the weaker the effect of adjacent cutter radial collaborative rock breaking. The installation polar angle difference affects the penetration of lateral cracks and inclined free surface. With the increase of the installation polar angle difference, the lateral crack connected to the inclined free surface becomes longer, and the cooperative rock breaking effect of by adjacent cutter in the circumferential direction of the cutterhead has been enhanced.This work analyzes the relationship between the arrangement of the cutter and the rock breaking performance of the cutter in the multi-cutter collaborative breaking rock condition, which provides a reference for the reasonable layout of the cutterhead cutter.

The accurate classification of vegetation species is the basis for the evaluation of vegetation restoration effect of coal gangue pile. In this paper, the visible image of coal gangue pile in different seasons was obtained by UAV remote sensing technology. The color space conversion and texture filtering were used to adequately explore the rich features of color, structure and texture in the visible image. Then, the traditional artificial feature selection method was improved, which could quickly, simply and efficiently screen features information to obtain the optimal classification features, and the optimized results were fused with RGB images to obtain multi-feature fusion images. Finally, based on two stages of RGB images and multi-feature fusion images, the vegetation of coal gangue pile was classified by three supervised classification methods, including support vector machine (SVM), maximum likelihood (ML) and neural network (NN). Meanwhile, the accuracy of classification results was evaluated by confusion matrix and the dynamic changes of vegetation were analyzed. The results showed that the improved artificial feature selection method could screen out the optimal classification features of coal gangue pile vegetation in different seasons. The selected classification features can not only effectively reflect the differences of various ground features, but also reduce the redundancy of feature information to improve the accuracy and efficiency of image classification. The classification result based on Support Vector Machine Classification (SVM) combined with multi-feature fusion image had highest classification accuracy, and the overall classification accuracy could reach 90.60%, and the corresponding Kappa coefficient is 0.8780, which was 9.74% and 0.1265 higher than that of RGB image of the same period, respectively. And, the accuracy of MLC and NNC classification methods was less improved. Compared with the RGB images of the same period, the overall classification accuracy could be improved by 6.95% and 3.93%, respectively, and the corresponding Kappa coefficient could be improved by 0.0845 and 0.0541, respectively. At the same time, based on the result of optimal classification, this paper evaluated the vegetation restoration effect of coal gangue pile in Changcun from the perspectives of vegetation coverage and vegetation allocation pattern. The results showed that a variety of different vegetation allocation patterns were adopted by the coal gangue pile, and the vegetation coverage in autumn and summer is higher than 75%. The overall effect of vegetation restoration was better. This study could provide reference for the identification and classification of coal gangue piles vegetation information based on UAV visible light image, and meanwhile provide opinions or suggestions for the later management and maintenance of coal gangue piles vegetation restoration.

Efficient analysis and utilization of coal mine safety big data is of great significance for improving the safety management level and production efficiency of coal mines. At present, there are some problems in coal mine safety big data governance, such as unclear data features and governance methods. In order to solve the above problems, this paper emphatically analyzes the features of coal mine safety big data. It is concluded that coal mine safety big data has 5V features, namely, large data volume (Volume), multiple data varieties (Variety), fast processing velocity (Velocity), low value density (Value), veracity (Veracity), and also has the features of inconsistent structural degree. This paper introduces the main data governance methods and models that can be applied to coal mine safety management. The methods are divided into five categories: single variable method, multivariate statistical analysis method, intelligent pattern recognition method, system dynamics model and comprehensive integration model. From the perspective of the subject and object, this paper puts forward a big data governance method system for coal mine safety. It is believed that the selection of data governance methods must be consistent with the data governance goals of the subject and object of intelligent mines. Selection of subject-based governance methods: the specific content of data governance is determined according to the needs, levels, tasks and security management objectives of data subjects. Selection of object-based governance methods: the specific content of data governance is determined according to the timeliness of object objects, throughput requirements and security management objectives. Finally, it is concluded that the determination of coal mine safety big data governance method needs to meet the common and individual needs according to the different scopes and objects under the unified goal and standard.

With an increasing mining depth and intensity in Chinese coal mines, unprecedented frequency and intensity of mining tremors are attracting extensive attention from the government and society. Under the initiatives from the government and the intensive investigations, significant progress has been made in the research and engineering practice, which greatly enhances the understanding and hazard control of the mining tremors. This paper reviewed the state-of-the-art occurrence mechanism, damage characteristics and control of the mining tremors in Chinese coal mines and demonstrated their main challenges. The conclusions are as follows: due to the complicated occurrence conditions of mining tremors, various definitions and classifications of mining tremors have been proposed from different aspects. This paper has summarized these definitions and classifications and defines mining tremors from special and general aspects, respectively, which classify mining tremors in terms of phenomena and occurrence mechanisms. Because mining tremors are widespread in all mining countries in the world, targeted mining tremor hazards prevention and control are urgently needed. Although the research started late in China, the hazard control of mining tremors and the emergency dealing capacity have been significantly enhanced in recent years due to the implementation of the regulations and rules from the government for mining tremors prevention and control. It has been summarized that from the macro view, the triggering of mining tremors is mainly induced by the coal pillar failure, roof breakage and movement and fault slip, and from the micro view, the triggering of mining tremors mainly includes tension rupture, implosion rupture and shear rupture. The mining-tremor-induced hazards have been surveyed in terms of source parameters, seismic wave attenuation and seismic wave disturbances, and the methods for evaluating surface and underground damage triggered by mining tremors have been also concluded. To achieve hazard source control and precise prevention, the current situation of mining tremors treatment in Chinese coal mines has been outlined. At present, Chinese coal mines, it is still far away to achieve accurate hazard source identification and full hazard control. Therefore, to support the national strategy of deep resources development and energy security, future studies should focus on investigating the hazard-forming mechanism, damage effect and prevention and control technologies of mining tremors.

According to some hot spots such as exploration before excavation，difficulties like drainage mining under special conditions and contradictory while operating procedures in recent coal mining water prevention projects, confusions brought to production practice and safety supervision are analyzed, some opinions are also put forward. Firstly, the connation of “doubt will be prospected” is discussed in this paper. It is assured that “doubt will be explored” comes after “prediction and forecast”. The “prediction and forecast” are key factors to problems like types of water hazards, water pressure and positions of water, based on what water exploration and release can be designed. From the historical background and realistic conditions, the analysis shows that the exploration before excavation proposed in [2011] No.70 document formulated by Shanxi Province is implemented under specific conditions, with strong pertinence (ancient wells and cellar water). The type of water damage is clear, the space position of water pressure source is roughly known, and the design conditions of drilling hole are available. Therefore, design conditions of water exploration drillings are acquired and “exploration before excavation” is reasonable. However, the scope of “exploration before excavation” cannot be extended infinitely to other fields, otherwise it will be aimless, causing bumps in design, execution and supervision. Secondly, degradation of water on soft rocks is analyzed. Degradations like crumble, rock mud, expansion and floor heave can happen on complicated soft rocks which possess weak cementation, low altitude, high expansion and strong watery, limiting production efficiency. The purpose of pre-dredging weak aquifer under soft rock condition is to improve the production conditions and to increase production efficiency. It is suggested that the regulations should make principles constraints on such drainage holes, so as to facilitate enterprises to formulate construction technical measures in combination with the actual situations. Otherwise, there will be a difference in understanding between government regulators and enterprises. Finally, according to the definition in the procedure, the water-conducting fracture zone does not include the caving zone (above the caving zone); nevertheless, the empirical formula in the procedure and the attached drawings show that the water-conducting fracture zone includes the caving zone, which has inconsistency between the front and the back. For this case, two alternative revision suggestions are advanced. Through the analysis of this paper, some fuzzy concepts are clarified, which is convenient for the production unit to accurately implement the rules and regulations, conducive to the precise supervision of safety supervision department. Besides, dilemma between the supervision department and the enterprise can be avoided.

In order to study the evolution of the microstructure characteristics of coal with increasing axial stress, this paper used NanoVoxel-3502E X-ray three-dimensional microscope and Deben in-situ loading test rig to carry out uniaxial compression tests of coal to obtain CT data under different strain conditions, Combined with the three-dimensional visualization software AVIZO, extracted the pores and fractures of the coal sample, studyed the pore and fracture distribution characteristics of the coal sample, and statistically analyzed the microscopic parameters of the number of pores, sphericity, and coordination number, curvature, thickness and other meso-structure parameters. It revealed the spatial distribution characteristics of the mesostructure of the coal sample under uniaxial compression and its distribution law over time, and the evolution law of the mesostructure with the axial stress. Studies have shown that small fractures appear in large numbers from 20 N to 732 N, and the number of pores increases. During the process from 431 N to 732 N, the concentrated distribution range of pore sphericity became narrower. Some pores and fractures gradually merged into the fracture network, and some pores and fractures were compressed. Part of the pores were compacted at 732 N, resulted in a reduction of 90,000 pores. The curvature of the fractures gradually increased, the fractures gradually became thicker, and the coordination number concentration ratio was higher. It also showed that the coal sample was internally connected. 732 N was the pinnacle of fracture network development. When the axial force reached 1100 N (peak), a complex fracture network was formed. With the advancement of the uniaxial compression process, although some pores and fractures were compacted at 732 N, due to the increase in axial force and residual load, the increase of pores and fractures was an inevitable trend, and there were still small pores and fractures after the peak, but the post-peak fractures were thinner, and the sphericity was more concentrated in 1.5-2.0. The curvature of the interconnected fractures was generally higher at the edges of the fracture network, the edges of the fracture network were fracture development zones. This paper provided a feasible technical means for studying the temporal and spatial evolution of coal samples, and has practical significance for interpreting the temporal and spatial evolution of the meso-structure of coal.

In order to reduce the occurrence of safety production accidents in coal mine industry, this paper combined the definition of safety behavior and unsafe behavior, behavior safety theory and MMEM system theory to put forward the standard definition of safety state of coal mine workers' behavior.According to the behavior influencing factors, this study established the coal mine workers behavior safety state evaluation index system, including 4 first-level indicators 21 secondary indexes.The Improved-AHP method, Entropy Weight method and variance coefficient method were adopted to determine the subjective and objective weights and weight combination.Taking one mine as example for analysis, this paper chose extension comprehensive evaluation method to construct the evaluation model. Results show that: For the coal mine industry, the defined-evaluation-improvement(D-E-I)model is universal.The empirical evaluation level is Ⅳ or "relatively safe".The evaluation results are in line with reality, and the model is scientific and practical.

The purification effect of coal mine groundwater reservoir on mine water mainly lies in the water-rock coupling between the rock mass and mine water.This paper systematically reviews the research methods of water-rock coupling in coal mine underground reservoirs, and presents the characterization methods of water quality and physicochemical properties of rock samples.It employs static simulation, dynamic leaching, cycle purification simulation and other tests to explore the purification regulation of mine water in coal mine underground reservoir, uses numerical simulation to obtain the selective adsorption trend of ions in the reaction process, and combines Piper three-line diagram, Gibbs model and correlation analysis to reveal the mechanism of water-rock coupling.The purification effect and research progress of suspended solids, specific ions and organic matter in coal mine underground reservoirs are discussed.The paper shows that underground reservoir of coal mine has a certain purification effect on mine water, and the purification effect of specific ions is mainly related to filtration and adsorption.Three research directions of coal mine underground reservoir purification technology in the future are proposed: ①developing large-scale and low-cost treatment technologies for underground mine water based on water-rock coupling purification, ②developing a "three-in-one" water quality control technology for coal mine underground reservoirs coupled with multiple water treatment technologies, and ③exploring the underground storage and resource utilization technology of concentrated salt wastewater for the future studies of water-rock coupling.

The problem of overlapping mineral rights of coal and gas is common in the Ordos Basin of China.The interaction will occur when coal and gas are mined simultaneously, so it is necessary to solve the synergistic mining problem to eliminate the accident potential.Considering that there are many constraints in the simultaneous exploitation of gas and coal, this paper proposed an energy control failure model by energy abnormal release and STAMP.This model explains the applicability of information transfer cycle and the energy control failure model.Then, through the analysis of gas-coal mining process, this paper established the interaction between the energy unit, barrier unit, and disaster-bearing body, and analyzed the characteristics of energy transfer and safety barrier interaction.Finally, by analyzing 9 kinds of accidental release scenarios, this study proposed the identification behavior methods and control measures to prevent gas-coal cross-mining accidents.

Faults are an important factor inducing mine safety accidents, and it poses difficulties on the identification of faults within 5 m of drop.Taking the Liupanshui coalfield of Guizhou province as the study area, this paper investigated the coalfield strata and carried out an on-site survey.It proposed a seismic physical model and used the unique velocity ratio of 1∶1.74 to realize the construction and analysis of small faults with a burial depth of 800 m, 1 000 m and 1 200 m and a drop of 5 m, 3 m and 1 m.This paper extracted a variety of seismic properties by seismic dynamics method to analyze small faults, and obtained the sensitivity of seven seismic properties to the characteristic response of small faults, including amplitude envelope, amplitude first derivative, and amplitude second derivative, and the correlation between seismic properties and drop was established accordingly.The results show that when the small fault drop of the coal seam is less than or equal to 5 m, there is a linear relationship with the traditional amplitude attributes, and a linear relationship with the seismic properties related to phase and frequency.There is high correlation between the amplitude envelope and the amplitude imaginary part, and low correlation between the instantaneous frequency, the amplitude first derivative, the cosine instantaneous phase, the amplitude second derivative and the amplitude envelope.

The video analysis and identification technology of coal mine safety production is the core technical support to ensure the intelligent construction of our country's coal mines and the high-quality development of the coal industry. In order to carry out real-time monitoring and early warning for potential safety hazards in coal mines, the key technologies of video AI (Artificial Intelligence) identification have become the research hotspot in the field of safety production in coal mines. In this paper, the development status of safety monitoring in the process of intelligent construction of coal mines are first expounded. Then, the problems of low efficiency, slow response and poor effect of the current mine video monitoring and safety hazard identification as well as early warning system are concluded. Combined with advanced technologies such as computer vision, edge computing, big data processing, cloud services, and intelligent terminals, the top-level design of AI recognition for coal mine safety production video is carried out. Furthermore, the “cloud-edge-terminal” collaborative computing system architecture of “human-machine-environment” global video AI perception in coal mines is also proposed, followed with a video recognition end node sensor, edge computing equipment, and video recognition scene cloud service application system constructed. By this way, the intelligent identification and early warning linkage control response mechanism are clarified, and the “cloud-edge-terminal” information interactive perception and linkage control data chain has been dredged, resulting with data sharing linkage and early warning coordination. At the same time, around the construction of the “human-machine-environment” global AI visual information intelligent perception and holographic generalized scene platform, the technical processing process of visual perception and identification and early warning of mine safety hazards has been sorted out. What’s more, the characteristic of the processing-enhancement-reconstruction-detection-recognition method are also summarized, and the mainstream direction and trend of the key technology development of coal mine safety production video AI recognition are also pointed out. Secondly, based on the application cases of representative mines such as Wangjialing Coal Mine and Baodian Coal Mine, the author demonstrates the latest progress and application effects of typical application scenarios in the process of coal mine safety production. Finally, according to the key technology characteristics of coal mine safety production video AI recognition, it is concluded that the existing coal mine safety production video AI recognition system has weak technical theory, different specifications of intelligent terminals, confusing application scenarios, poor data compatibility and linkage closed-loop ability, weak database security, inconsistent evaluation mechanism as well as imperfect application standards, etc. Subsequently, this paper pointed out that the future development direction is to strengthen the research on key technologies and theories of video AI recognition, establish and improve intelligent terminal hardware specifications and applicable systems and build a new coal mine information multi-dimensional active perception model and industrial internet application platform with unified standards, perfect mechanism, real-time interconnection, dynamic prediction, collaborative control, safety and reliability, which gradually form a high-precision intelligent perception field of holographic generalization in the whole mine, so as to realize the precise perception of the underground "human-machine-environment" global video information and the coordinated control of danger sources.

In order to explore the possibility of using laser induced technology to produce coal-based graphene by using coal as carbon-containing precursor, this paper chooses high volatile bituminous coal in Wajinwan and low volatile bituminous coal in Tashan as carbon sources, and uses laser induced technology to produce coal-based graphene. Raman spectroscopy (Raman), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) were used to characterize raw coal and the products after laser irradiation. The results show that after laser irradiation, the Raman spectra of the products have a typical 2D peaks and sharp G peaks, indicating an alignment structure for the products generated. XRD results show that the diffraction peaks (002) and (100) become narrow and sharp, and the layer spacing is 0.345 nm. XPS results show that the C=C bond and π—π interaction of sp2 are enhanced after laser irradiation of bituminous coal, forming sp2 network aromatic layer. The layered porous structure of the sample after laser irradiation was observed by SEM, HRTEM results show that the aromatic fringe has the characteristics of few graphene layers, the graphene layers are mostly concentrated in 2−10 layers, and the layer spacing is 0.346 nm, which is basically consistent with the XRD results. All these data indicate that bituminous coal has been formed into coal-base graphene after laser irradiation. However, limited by the number of samples used in this paper, this study is only a preliminary understanding, and further research needs to increase the number of samples.

CHN Shendong Coal Group Co.,Ltd (hereinafter referred to as “Shendong Company”) is the backbone coal production enterprise of the China Energy Group. It has made remarkable achievements in safe and efficient coal mining, domestic high-end equipment manufacturing, intelligent mine construction, safety management mode innovation and green ecological low-carbon, leading the scientific and technological innovation of the China coal enterprises, it has created many world firsts in the aspects of fully mechanized mining height, per capita work efficiency of the mine, long-term safety management of the mine and the construction of a hundred million ton mining area management and control center. This paper systematically introduces the progress of Shendong Company in science and technology management, innovation platform, collaborative innovation, talent team, intellectual property rights, standard system and scientific and technological achievements, and summarizes the innovation driving system of Shendong Company and the scientific and technological innovation channel of spiral acceleration. In terms of mining technology innovation and practice, this paper combs the technical breakthrough of Shendong Company in gradually increasing the mining height of full height fully mechanized mining from 6.3 m to 8.8 m, the mining technology of fully mechanized mining in the upper layer of shallow hard and extra thick coal seams and upper layer fully mechanized mining lower layer fully mechanized caving was introduced, the technical problems, key equipment and technologies faced by equal-height mining were sorted out, and the technical adaptability of short wall mechanized full caving method and the technical practice of non pillar mining method were analyzed; this paper introduces the complete set of fast intelligent tunneling system and the key technology of tunneling anchor integration, which improves the tunneling efficiency and solves the contradiction of “Imbalance in mining and excavation”. In terms of research, development and application of domestic high-end equipment, this paper introduces the breakthrough achievements made by Shendong Company in the equipment matching of the world's first 8.8 m super large fully-mechanized mining face, and analyzes the technical difficulties and innovation approaches faced by the first set of water hydraulic support in China, this paper analyzes the breakthroughs of 6 000 m retractable single point drive belt conveyor in the research of resistance reduction technology for the whole machine, tension control and intelligent frequency conversion drive technology, summarized the experience of developing the world's first double hundred ton heavy haul carrier to break through technical barriers, and enumerates the technical innovation achieved by applying new energy mining electric vehicles to the underground. In the aspect of intelligent mine construction, in view of the problems faced by intelligent coal cutting and machine following rack in the face of intelligent coal mining face, the technical innovation realized by Shendong Company in the process of intelligent coal mining face is summarized; sorted out the pioneering journey of intelligent coal preparation plant from scratch; for the first domestic coal mine operating system in China: Mine Harmory operating system, the key technology core and the value of popularization and application are analyzed; this paper analyzes the integrated technology used in the construction of the first 100 million ton mining area digital centralized management and control platform in China, and introduces the innovation and practice of 13 kinds of underground intelligent robots. In terms of safety management technology and practice, this paper has established the “135” work method safety risk management and control management system, which has realized the ultra long safety production cycle of ten million tons of coal mines; the mine pressure control system of Shendong Company and the intelligent cloud platform for dynamic and efficient early warning of mine pressure have been established, forming the unique mine pressure control technology system of Shendong Mining Area; and introduces the technical system of water, fire and gas disaster prevention, which ensures the construction of safety management system of Shendong Company.In the aspect of green ecological construction, this paper introduces the achievements of Shendong Company in the green development and technological innovation of coal, expounds the technical practice in the development of ecological mines, green mines and clean coal, and introduces the Shendong Pioneer Demonstration Area in the implementation of the major national strategy of ecological protection and high-quality development in the Yellow River Basin. By summarizing the scientific and technological innovation system and innovation achievements of Shendong Company, this paper probes into the thinking of the future scientific and technological development of coal mines, and clarifies the development direction of its scientific and technological innovation system and major scientific and technological breakthrough.

How to solve the contradiction between coal mining and soil and water conservation is the key scientific problem to realize the ecological environment protection and high-quality development in the middle reaches of the Yellow River. In this paper, taking the coal mining subsidence area in loess gully of northern Shaanxi as the research object, aiming at the typical geological occurrence characteristics of the main coal seam, and taking the underground mining thickness (9, 7, 5 m), the natural slope shape (straight slope, concave slope, convex slope, compound slope) and slope (5°, 15°, 25°, 35°, 45°) of the surface loess as variables, a total of 60 numerical models are constructed. In this paper, based on FLAC3D numerical simulation software, the evolution process and law of slope morphology under the coupling effect of loess natural slope morphology and mining thickness are studied. Then, based on China soil erosion equation (CSLE model) and empirical model, the soil erosion effect of subsidence slope is calculated and analyzed. The results show that: ① Coal mining subsidence will lead to the increase of the slope of the surface loess slope, and the greater the mining thickness, the greater the slope increase. Significant Amplification Effect of Large Mining Thickness on Slope Gradient Increase of Surface Loess Caused by Coal Mining Subsidence. The concave slope generally has a significant effect on the slope of the subsidence slope, especially under the conditions of “ mining thickness 5 m, natural slope > 5 ° ”, “mining thickness 7 m, arbitrary natural slope ”, “ mining thickness 9 m, natural slope ≤ 35°”. No matter what kind of mining thickness and natural slope shape, the natural slope of ≤ 5 ° has the greatest influence on the increase of subsidence slope. ② Coal mining subsidence will lead to the increase of M1 on the surface loess slope under the scale of “ annual erosion rainfall ”, and the greater the mining thickness, the greater the increase of M1. When the mining thickness increases from 5 m to 9 m, M1 increases by about 1 time. The concave slope of four slope shapes has the greatest influence on the increase of M1 on the subsidence slope. The natural slope of ≤ 15° has a great influence on the increase of M1, which is more than 20% under the condition of “ mining thickness 9 m, concave slope ”. ③ Coal mining subsidence will lead to the increase of M2 of surface loess slope under the scale of “ typical erosion rainfall ”, and the greater the mining thickness, the greater the increase of M2 ; when the mining thickness increases from 5 m to 9 m, the increase of M2 increases by about 1 times. The concave slope of the four slope shapes has the greatest influence on the increase of M2 on the subsidence slope. The natural slope of ≤ 15° has a great influence on the increase of M2, which is more than 17 % under the condition of “ mining thickness 9 m, concave slope ”. The results can provide scientific basis for accurate prevention and control of soil erosion and high-quality development in the mining area of northern Shaanxi and even the middle reaches of the Yellow River Basin.

The mine 5G is the foundation of intelligent mine construction. In order to meet the diversified application requirements of intelligent mine, it is necessary to promote the realization of mine 5G-advanced communication evolution system through 5G-advanced communication evolution technology. The current status of mine 5G technology research and system deployment is reviewed. The mine 5G has preliminarily realized audio and video call, HD video analysis, equipment remote control and other applications. However, there are some problems such as single terminal form, heavy uplink load, separate construction of 5G-advanced communication system and positioning system, etc. This paper analyzes the applicability of 5G-advanced communication evolution technology of 3GPP Release 17 in mine 5G-advanced communication. It is pointed out that RedCap lightweight terminal technology, NR direct connection communication technology and NR positioning technology will become the key technologies of mine 5G communication evolution. The key technologies of mine 5G-advanced communication evolution are studied. RedCap lightweight terminal technology can meet the research and development requirements of low-power consumption and low-cost multimode terminals of mine wireless sensors, single-channel wireless transmission mine video monitoring equipment, intelligent miner lamps and intelligent wearable devices. NR direct connection communication technology is applied to mine automatic driving vehicle-mounted terminal, roadway side equipment and emergency communication relay equipment. It can meet the requirements of low delay and high reliable transmission of mine automatic driving and emergency communication. NR positioning technology is applied to mine communication and positioning integration to meet the technical requirements of mine communication and positioning system fusion. This paper puts forward the architecture of mine 5G-advanced communication evolution system. The study provides the direction for building 5G fully connected mine, supporting multi-link wireless access and realizing the integration of communication and perception.

Organophosphine compounds have broad application prospects in industrial production and daily life. Their flexible polar and nonpolar groups make them have adjustable properties. There are many kinds of organic phosphine compounds and their derivatives, and their physical and chemical properties are also different, which makes organic phosphine compounds more and more widely used in production and life, especially in beneficiation and metallurgy. This paper lists some organic phosphine agents that have obtained good data in laboratory test or excellent performance in industrial application, and some representative phosphorus compound beneficiation and metallurgy reagents. Referring to some current research results and combined with production practice, this paper makes a specific classification research on them, and looks forward to their future development and application trend.

The rock bolting construction equipment is an important part of the complete set of bolt support technology in coal roadway, which directly affects the speed and quality of rock bolting. After a long period of development, China's coal mines have developed various forms of rock bolting equipment, including single bolter, mobile bolter, roadheader bolter, bolter miner, bolter conveyor and straddle bolter. This paper systematically analyzes the development history, technical performance, technical parameters, applicable conditions and latest development of six kinds of rock bolting construction equipment. The single bolter is light, flexible and mature in technology, forming a series of products, which are widely used. The onboard bolter can be integrated on different platforms to form a variety of integrated construction equipment. The mobile bolter has formed a variety of models from two arms to nine arms. It can closely follow the heading equipment, work alternately with the heading equipment, and complete the rock bolting construction with multi-arm cooperation and multi-arm parallel operation. The onboard bolter is equipped on the cantilever roadheader, and various types of roadheader bolters are developed, realizing two functions of heading and bolt construction. The bolter miner has realized localization. The bolter miner with forward moveable bolting platform, shield type bolter miner and bolter miner with the integration of drilling and bolting are developed. The bolter conveyor from two arms to seven arms and the ten-arm straddle bolter are developed. The rock bolting, heading and transportation have been carried out in different zones. This paper introduces the technology and equipment of rock bolting with the integration of drilling and bolting. They include bolt with the integration of drilling and bolting, pump-injected anchoring agent, onboard bolter with the integration of drilling and bolting, drill box, rock bolt bin, anchoring agent pump-injection system and intelligent control system. The traditional six-step rock bolt construction process is simplified into one continuous process. It realizes the automatic operation of 'one key rock bolting', significantly improving the speed and automation degree of rock bolting. The paper points out the development trend of rock bolting construction equipment in coal roadway. The trend includes following aspects: the digital intelligent bolt onboard bolter, onboard bolter positioning, pose self-adjustment and multi-onboard bolter collaborative control technology; the optimization of bolt (cable) structure and materials, upgrading of anchor grouting materials and improvement of construction equipment; the environmental dynamic sensing and stability discrimination of surrounding rock with heading; the fault diagnosis technology of rock bolting construction equipment and the online monitoring of roadway surrounding rock deformation and bolt load; establishing a big data platform to realize automation and intelligenitization of rock bolting.

Based on the basic concepts and connotations of digital twin, this paper analyzes the application advantages of digital twin technology in coal mine power grid. The operation management of the coal mine power grid is assisted by two means of synchronous entity operation status and digital simulation operation. The technology has the characteristics of data-driven, real-time update and synchronous feedback. The basic framework of the digital twin system of the coal mine power grid is proposed. The framework is composed of physical entity layer, digital twin model layer, user service management layer and data exchange layer. The operation mode of the digital twin system of the coal mine power grid is explored from two aspects of the physical entity and the digital twin model. This paper introduces the key technologies for establishing the digital twin system of the coal mine power grid. The technologies include digital twin model construction of coal mine power grid, intelligent data acquisition, intelligent communication based on 5G, digital twin intelligent database, and digital twin equipment intelligent management platform. The application scenarios of digital twin technology in the coal mine power grid are proposed. The scenarios include the condition evaluation of underground electrical equipment, fault location and protection of the coal mine power grid, intelligent monitoring of the coal mine power grid and intelligent inspection of underground lines. The digital twin technology is applied to the coal mine power grid to carry out dynamic simulation modeling on the state and operation of the coal mine power grid. On the one hand, the higher operation requirement of the current large-scale coal mine power grid relative to the ground power grid can be met. The safety of coal mine production can be guaranteed. On the other hand, the intelligent process of the coal mine power grid can be promoted. The efficient and reasonable utilization of data resources can be realized.

Based on a large number of field investigations and the analysis of the "analogous hyperbolic" overall movement model proposed by the author, this paper further extends it to three-dimensional space, and proposes a full-space "analogous hyperboloid"three-dimensional movement model of the mining strata.There are two types of hyperboloids, "quasi-single-leaf"and "quasi-double-leaf", which can approximately describe the three-dimensional movement and surface subsidence characteristics of full-space mining strata under different lithological conditions.The "analogous single leaf hyperboloid" model is a horizontal moving boundary model of the spatial rock layer, which is implicit in the thick loose layer overlying rock; the "analogous double leaf hyperboloid" model is the vertical movement of the spatial surface subsidence and the overlying fissure arch and caving arch.The boundary models are approximately symmetrical with the "origin" in the main key layer, and are embodied in external forms such as surface subsidence under mining disturbance and arch caving of the surrounding rock in the stope. Through theoretical analysis, similar model test and 3DEC numerical simulation, this paper deduces and proves in detail the "analogous hyperboloid" model of spatially mined rock strata movement and surface subsidence under the condition of near-horizontal coal seam mining in thick loose layers.At the same time, this study analyzed the composition conditions, influencing factors and overall migration law of the co-asymptotic conical surface "analogous hyperboloid" model.Results show that under the condition of near-horizontal coal seam mining with thin bedrock and thick loose layer, the "quasi-hyperboloid" theoretical model is in good alignment with the 3DEC simulation results, indicating that the overlying rock migration and surface subsidence in space mining are "analogous hyperboloid" feature.

If the shearer is cutting coal using the "memory cutting" technique, a manual demonstration is required.The memory cutting technology has higher requirements on the reserving conditions of coal seams.When the coal seam fluctuates greatly, frequent manual demonstrations are required.The "memory cutting" technology only optimizes the cutting path of the coal seam roof for the next cutting.Along the advancing direction of the shearer, it is impossible to accurately plan and control the pitching angle of the shearer according to the reserving conditions of the coal seam.Based on the concept of shearer self-adaptive intelligent cutting, this paper designs the operation mode of the shearer intelligent cutting system in the fully mechanized working face.In this model, the high-precision three-dimensional geological model of the working face is first constructed by using the highly accurate geophysical data of the coal seam, and then the future cutting path of the shearer is planned by using the model.At the same time, the high-precision three-dimensional geological model is dynamically corrected by using the latest geological data of the working face during the mining process.In this paper, the high-precision three-dimensional dynamic geological model is coupled with the shearer mining planning algorithm.According to the model, a shearer mining control baseline planning algorithm that can adapt to the changes of the coal seam is proposed, which realizes the pitching control of the shearer in the advancing direction and the cutting control in the pulling direction, as well as the efficient cooperation between the update of the geological model, the planning of the mining baseline and the adjustment of the shearer drum.The calculation service interface of the drum adjustment parameters in the intelligent cutting system and the communication protocol between the intelligent cutting system is designed.Addtionally, the shearer control system is considered.This realizes the precise control of the shearer drum based on the planning cutting path.The intelligent cutting system of fully mechanized working face is applied to guide the production of shearers.The practice shows that the shearer intelligent cutting system is suitable for coal seams with various degrees of floor inclination.The cutting line of the shearer can better fit the roof and floor lines of the coal seam, which can save resources and improve production efficiency.

In order to find out the key causes of changes in spontaneous combustion characteristics of igneous intrusive coal seams, this paper took the Daxing Coal Mine in Tiefa Coalfield as example for analysis, which was widely invaded by igneous and had serious coal spontaneous combustion disasters.Metamorphic coal and unaffected primary coal were collected from the study area.Specifically, this paper studied the patterns of heat production and temperature rise, gas production rules, and microscopic structure parameters of coal samples by synchronous thermal analyzer and coal spontaneous combustion characteristic measuring device.The experimental results show that the igneous intrusion caused the mutation in the spontaneous combustion characteristics of the coal.Compared with the primary coal, there was significantly higher oxidation heat release of the metamorphic coal at the low temperature stage.Also, the crossing point temperature of metamorphic coal was reduced by 13.2 ℃, and it entered the stage of oxidation and weight gain earlier than the primary coal.When the environment temperature exceeded 90 ℃, the oxidation heat generation and reaction rate of metamorphic coal increased rapidly, which showed higher oxygen consumption rate and faster generation rate of oxidative gas products such as CO and CO2.This demonstrated higher oxidation activity of metamorphic coal than that of primary coal.The analytic results of physicochemical microstructure showed that the high temperature and pressure of igneous intrusion changed the pore structure of coal, which reduced the pore volume and specific surface area of micropores/mesopores in metamorphic coal, and the pore volume of macropores was three times higher than that of primary coal.The average pore size and porosity increased significantly, which was conducive to the transport, migration and adsorption reaction of oxygen molecules in the coal structure.At the same time, igneous intrusion reduced the oxygen-containing functional groups of metamorphic coal, and the content of aliphatic hydrocarbons with higher activity increased from 27.98 % to 29.07 %, which enhanced the oxidative activity of metamorphic coal.Moreover, igneous intrusion caused problems such as increased air leakage, long oxidation time of left coal, and wide oxidation zone during the mining, eventually leading to severe coal spontaneous combustion disasters.

With the increase of coal mining depth, the stress environment of the surrounding rock of the roadway deteriorates, therefore it becomes a prominent problem for the large deformation of the surrounding rock and the breaking of the bolt and cable, which seriously affects the safety of deep mine production.To solve such problems, this paper focuses on the advantages and disadvantages of bolt and cable support.Based on the interaction mechanism between Anchor Cable with C-shaped tube(ACC)and surrounding rock, this paper proposed a new ACC support technology.ACC optimizes the stress state by improving the structure of the free section of the anchor cable.It can not only enhance the anchor cable's axial bearing capacity but also prevent the free section of the anchor cable from breaking due to lateral action.It can avoid the problem of instability of surrounding rock.Through the shear test, it is found that the maximum shear load of the ACC is more than 1.27 times that of the ordinary anchor cable, and the average maximum shear displacement is 1.16 times that of the ordinary anchor cable, which indicates that the ACC has good shear resistance and shear direction extension properties.Based on the engineering case of the roadway of Jiulong Mine, this study analyzes the deformation and failure characteristics of the roadway under the original support scheme through on-site monitoring and borehole detection, and has successfully applied the ACC in the deep large-deformation roadway.The field monitoring results show that the new technology of ACC can effectively control the large deformation of surrounding rock.The results of this study can provide reference for similar deep mine support.